Thursday, November 9, 2017

Changing Brake Fluid and Brake Hoses in Bentley and other High End Cars

All high end carmakers recommend replacement of brake fluid.  The only thing that varies is the interval, which ranges from one to three years on most brands.  The reason for the change is that DOT3 and DOT4 brake fluids are hydroscopic; that is, they absorb water.  The water causes rusting of brake components from inside, which causes caliper failure.   Fluid with moisture in it also has a lower boiling point, and cars that are run hard can suffer sudden brake failure if the fluid boils on hard braking.  Finally, the fluid picks up particles of rubber from seals and hoses and that can contribute to sludge formation that clogs critical components if left in place.

In addition to the manufacturer recommendations car clubs and race tracks often have their own rules for brake fluid flushing before track events.  At Robison Service we recommend following the manufacturer or track change recommendations with one caveat:  If the car lives in a humid area we recommend checking moisture content periodically with a test strip and changing early if it becomes excessive.

Carmakers also recommend periodic replacement of the brake lines.  Your brake lines flex with every movement of the tires, and they are subject to deterioration from oxidation (dry rot) just like all the other rubber bits on your car.

Most carmakers recommend brake hose changes at intervals ranging from 6 to 10 years.  Land Rover and BMW have both had recall when they began seeing hose failures in the field.  Brake hoses are critical parts that are not easy to evaluate externally and they are critical to your safety so I recommend they be changed by the schedule, and certainly when ten years old.

In some cases the carmakers also want us to replace the steel pipes adjacent to the front brake hoses because they are stressed from the combination of steering and the suspension’s up and down movement.  Bentley is an example of a carmaker who does that.  Here is an illustration of a hose update on a Bentley GT.  Other high end cars will be similar.

In this photo you can see the front hose assembly on the car:

Here is the rubber hose and steel pipe, removed from the vehicle.

Bentley wants us to replace the screws and retaining clips as well, as you see here:

In the back of the Bentley GT there are 6 rubber hoses, all of which need to be changed:

Once the hoses are changed the brake system has to be thoroughly bled.  You can get a jump start on this by using a pressure bleed system and letting fluid flow through to each wheel, but you will probably need a factory test system for the final phase to activate the ABS/DSC pump and bleed that.  Older cars won’t have that but any high end vehicle from 2000-onward will.

On some cars, hose replacement is limited to four hoses.  The Porsche 911 is an example of that, and the job can be done in a few hours.  Afterward the fluid flushing takes up another hour.  Cars like the Bentley GT require replacement of some steel pipes in addition to the hoses, and on the Bentley there are 6 hoses, not 4.  Cars like the Bentley will be most of a day's work to service.

The most time consuming cars are the older Rolls-Royce and Bentley which have unique braking systems with 20 or more hoses.  Those cars can be 20-30 hours of labor to update hoses and flush fluids.

On older cars don't be surprised if you have to replace some of the steel lines.  If they are old and rusty they may break when the hoses are unscrewed.  The car in the photo below needed new steel lines in addition to the rubber hoses:

It’s important that you use the correct brake fluid.  DOT3 is the fluid used in most cars through the 1980s.   At that point DOT4 came along as a higher performance fluid, and we use that in place of DOT3 almost everywhere today.

DOT4 is the standard fluid in most current cars.

DOT5 is a silicone synthetic fluid that is popular in some antique car circles because it won’t damage paint.  We have seen problems when DOT3/4 systems were changed to DOT5 and experienced failures, so we discourage that practice now.

Some cars need lower viscosity brake fluids for high performance stability control, and for those vehicles we use variants of the traditional DOT4 fluid.

When you change hoses you should always inspect the pads and rotors.  With most cars the rule of thumb is that the friction material must be at least as thick as the metal brake backing plate.  In the car below (a Bentley GT) the pads are about twice as thick as the backing plate.

Another think I suggest is that you make sure the pads are free in the caliper, and all the sliding pieces are free and greased if necessary.  Note that some cars use lube on the calipers and others don't.

© 2017 John Elder Robison

John Elder Robison is the general manager of J E Robison Service Company, celebrating 30 years of independent Bentley, Rolls-Royce, BMW/MINI, Mercedes, and Land Rover restoration and repair in Springfield, Massachusetts.  John is a longtime technical consultant to the car clubs, and he’s owned and restored many fine British and German motorcars.  Find him online at or in the real world at 413-785-1665

Reading this article will make you smarter, especially when it comes to car stuff.  So it's good for you.  But don't take that too far - printing and eating it will probably make you sick. 

Tuesday, October 3, 2017

The Philosophy of Oil Changes and Inspections

Automobiles of today are far less maintenance-intensive than those of a generation ago.   Fluids, filters, and spark plugs all last longer.   Cars once required service every three months or 3,000 miles.  Now the most basic service – an oil change – has moved to a 12-15 month or 7,500-15,000 mile interval. Now that “tune ups” have been rendered obsolete by computerized engine management, carmakers realized that the oil change was the basic unit of auto service understood by most motorists.  Carmakers therefore want to make them as inexpensive as possible, and they have pressed their dealers relentlessly to do that.

Dealers and quick lube centers market oil changes as commodity services that can be performed quickly while people wait.  The basic service consists of draining and refilling oil, changing the filter, checking the under hood fluids, setting tire pressures, resetting the oil service reminder and looking for warning lights or obvious problems.

In theory, a trouble-free car might only visit a service department once a year.  That left us uncomfortable with the basic service the dealers and quick lubes were touting, and it led us to a philosophy we adopted about ten years ago.

If we were only going to see a car once a year, we reasoned, it made sense to have a skilled technician do the service.  Our idea was that a skilled tech would be more likely to spot incipient issues than a less highly qualified lube person.  We felt that it made sense to allow the tech an extra half an hour to look the car over.  We left it to the tech to decide what any particular car needed – maybe it was pulling a wheel to look at a brake caliper that might be dragging, or perhaps it was running a system scan with the diagnostic tool to look for hidden electronic issues.  Our thought was to budget enough time for a careful inspection.

Those comprehensive examinations often revealed problems owners hadn’t known about, like water pumps that were starting to leak or electronic codes that warned of impending module failures.  For the most part, the enthusiast clients we served appreciated the extra attention we gave their cars.

The only problem with such a service philosophy proved to be cost.  Labor rates in most shops rose significantly in the past 10-15 years.  In most of the country, shop rates for high-end cars now range from $120-180 per hour.  At the same time, cars got more complex and it takes more time to do these more comprehensive inspections.  An extra half or three quarters of an hour added $75-120 to the bill, a noticeable amount for many.  Meanwhile, charges for basic oil service at many dealers held steady, or went down.  By packaging the inspection with the oil change, we were selling a different and more expensive service, but to a potential client on the phone, it seemed the same.

Labor was not the only area of concern, when it came to cost.  Carmakers like BMW and Mercedes brought out private label oils priced lower than more broadly compatible synthetics like Mobil 1.  Mercedes (for example) began recommending changing oil with a siphon system to avoid lifting the car, and they moved the filter under the hood in support of that.  Dealers of all makes were encouraged to build quick lube bays in the manner of Jiffy Lube.  Those measures and manufacturer pressure has kept basic oil change prices down in many areas.

That put independent shops like ours in an unusual position.  With the addition of a comprehensive look over, our oil changes were significantly more expensive than oil changes at the dealership.  Independent garages are widely perceived as less expensive alternatives to the dealer, and with this move, that notion was turned on its head.

Through my writing on the car business I have gotten to know many dealer service managers, as well as factory service reps and independent service professionals.  From our conversations a new oil change and inspection philosophy has emerged. 

Most new cars start out being serviced at the dealer.  When the warranty expires owners often shop around for alternatives.  That is the moment when the quoted oil change price may keep a motorist with the dealer or send them elsewhere.  Often those relationships initially turn on a phone call.  A dealer client has less incentive to try alternatives if alternative providers quote a higher price for what the motorist feels is a basic service. 

For someone who calls with the idea of comparing our service department to the one at the dealer, the fact that our oil service includes a thorough check is often irrelevant, because it's not understood. The caller was seeking to make a comparison, and if our number is bigger, we seem more expensive and that may end the exploratory call then and there.

Years ago, I felt shops compromised quality by doing quick, low cost services.  Now we see an alternative.  We treat oil changes as quick, inexpensive, commodity work that is limited in scope to what the words say.  Where we once thought the oil change was likely to be the car’s once-yearly visit to our shop, we now realize that most older cars will be back at least once for resolution of a problem.  Perhaps a warning lamp has come on, or the engine is leaking coolant.  When the car comes in for those issues, we ask if they’d like us to look it over for other problems or concerns.  99% of the time, the answer will be yes. 

We have shifted the time we spend inspecting cars for incipient problems from the oil change visit (a quick commodity service) to the repair visit (a more open ended and less commoditized visit.)

Given that most cars will have at least one of each kind of visit in a year clients still receive the same annual inspections, the price of the commoditized oil change remains low, and the overall service cost remains about the same.  The same value is provided, the only change being some things come at a different time. 

For those who ask, we will do a comprehensive inspection at any time but on the bill we keep it separate from the oil change.  We've learned to distinguish this basic service from the "small service" which combines oil change and inspection, and we've also learned to tell customers when the car or mileage calls for more than just an oil change.  Our advisor makes this point to clients before work is done.  Sometimes clients want "just an oil change" but other times, they wanted the complete mile-appropriate service but did not know how to ask for it.

In that case, we do what's appropriate.  That's also what we do when someone says "change the oil and look the car over for the season."  Before beginning, we explain what we will be checking, and roughly how long it will take and how much that will cost.  Time varies by car and condition, and we've careful to explain that this is "much more than just an oil change," the basic unit we build upon.

On a modern car that is driven daily an oil change and thorough check over might take 1-2 hours in total.  On a collector car the time needed for though inspection will be longer, and older cars usually have more points for lubrication.  Older cars are also more likely to have adjustment needs where those jobs are done by computer on newer models.

The tasks of auto service continue to change and evolve, but at some level the oil change remains the same.  It will probably continue to be the basic unit of car service until electric cars render that task obsolete, except on collector cars, aged cars, and commercial vehicles.  I will probably be retired when that happens but the next generation will confront a new set of challenges as maintenance of transport machinery never goes away; it just evolves.

To some this may seem like sizzle, as opposed to steak.  That may be, but in many situations, sizzle is the basis for choice.  Our goal is to provide the best service at fair prices and to do that, we must start by bringing new clients through the door.  That is going to be harder if we start at a perceived price disadvantage, whatever the reality may be.

When dealing with a car that provides day to day transportation I believe it's cheaper to head off a breakdown with preventative maintenance.  I'd rather have my car looked over for potential problems by someone I can trust to be competent and truthful. I'm happy to pay the extra time a look-over takes.  Other people don't share that particular point of view, and they want their oil changed and nothing more.  For them, a basic no frills oil change is the ticket, and when their car breaks down, we can offer an inspection.

© 2017 John Elder Robison

John Elder Robison is the general manager of J E Robison Service Company, celebrating 30 years of independent Bentley, Rolls-Royce, BMW/MINI, Mercedes, and Land Rover restoration and repair in Springfield, Massachusetts.  John is a longtime technical consultant to the car clubs, and he’s owned and restored many fine British and German motorcars.  Find him online at or in the real world at 413-785-1665

Reading this article will make you smarter, especially when it comes to car stuff.  So it's good for you.  But don't take that too far - printing and eating it will probably make you sick.

Thursday, September 7, 2017

Air suspension on Bentley GT and Flying Spur series cars

The Bentley GT-series were the first cars from Crewe to use air suspension instead of conventional steel coil springs.  In doing this Bentley followed the lead of corporate parent VW (and Audi) along with Mercedes, BMW, and Land Rover.  Air suspension allows for lowering the car at speed, raising it for clearance, and even leaning into corners.  It’s a more sophisticated system but it does introduce some new service problems as the cars age.

Coil springs sag with age, but since 1966 Bentley had provided means to shim the springs to compensate.  With that, coil springs usually last 20 years.  Air springs don’t sag, but the rubber air bladders can crack and leak, and when that happens there is no compensation – they must be replaced.  Air springs may begin leaking when the car is five to ten years old.  Note that air leakage in the struts is seldom visible, even if it's sometimes audible.

The air bladders surround the shock absorbers in these cars, which means they are serviced as a unit.  Older Bentley motorcars had separate coil spring and shock units.  

In the Bentley parts catalog a Continental GT air strut is somewhat more expensive that a comparable shock and spring for, say, a 1997 Continental R.  As of this writing, OEM Bentley front struts are about $2,500 each.

Bentley GT cars have a sophisticated multilink suspension that is shared with other VW/Audi models.  When removing the struts it is necessary to disconnect several of the suspension links and it’s common to find the top links have all broken or deteriorated.  If that’s the case they should be replaced too, which adds another $300 apiece at the Bentley parts counter.

Upper suspension links usually need replacement when struts are changed

The rear suspension uses similar components but seems to be a bit more durable, perhaps because the struts go up and down but do not twist for steering.  When the rear suspension needs service the issues and corrective actions are the same.

One benefit of the GT’s shared mechanical platform is that many parts interchange with high end VW/Audi cars, often at lower prices.  The Bentley parts are the same in some cases; in others they are slightly different.  Many buyers of secondhand Bentley cars will choose the VW replacement parts even if they are slightly lower performance, given cost savings of 10-40%.

Aftermarket front strut for Bentley GT

Furthermore, shared platform parts are often available from aftermarket suppliers giving even more range of choice, performance, and cost.  As of this writing (fall 2017) it's possible to save more than 50% off the cost of genuine Bentley struts with good aftermarket units.  For the most demanding applications, only the genuine stuff will do but for the other 95% of the time . . .

Most Bentley dealers will stick to the genuine Crewe parts bin.  Independent Bentley specialists are free to source parts anywhere.  One caveat:  If a car is repaired with genuine Bentley parts at a dealer the whole repair will be covered at any Bentley dealer in the country.  Genuine parts put on by an independent will also be warrantied at any dealer, but not the installation labor.  Repairs with aftermarket parts will only be covered by whatever warranty is offered by the parts supplier and shop.

Another point to keep in mind is that strut replacement may be within the skills of a mechanically inclined owner, but the Bentley laptop test system will be needed to clear faults and bring a flat suspension back to life.  If you have a car whose suspension has gone flat, simply replacing the failed parts will not return it to function.  The computer must be reset.

Luckily there is a modestly priced answer for that, too.  The VAG system will run on any Windows laptop and costs less than $500 and do everything but programming.  You can buy a pass-thru system to add dealer-level test and programming for approximately $2,000 more but you also need a subscription to the online Erwin system.

© 2017 John Elder Robison

John Elder Robison is the general manager of J E Robison Service Company, celebrating 30 years of independent Bentley, Rolls-Royce, BMW/MINI, Mercedes, and Land Rover restoration and repair in Springfield, Massachusetts.  John is a longtime technical consultant to the car clubs, and he’s owned and restored many fine British and German motorcars.  Find him online at or in the real world at 413-785-1665

Reading this article will make you smarter, especially when it comes to car stuff.  So it's good for you.  But don't take that too far - printing and eating it will probably make you sick.

Sunday, September 3, 2017

Vintage Cars and Flood Damage - Can They Be Saved?

Among the hundreds of thousands of cars flooded by Hurricane Harvey there are some collector vehicles, and owners will face the challenge - what to do with them?  Modern cars are usually insured, and fairly easily replaced.  It can be a hardship, but there is no fundamental barrier to replacing a 2009 Cadillac or a 2013 Toyota.  Mercedes S65 AMGs may be rare and exotic, but they are still making more of them.

What about your 1960s Barracuda or Lincoln?  What about the XK120 Jaguar from the 50s?  They aren’t making any more of those, and replacement may not be an option.  Even if it is insured, the car may have great sentimental value.  You don't want "any" 1963 Chevy, you want the one your dad took cross country, long ago.  Or maybe you are willing to get another car, but nothing comparable exists.  Perhaps you just spent two years restoring that car that just went in the water . . . 

At the same time, replacement may not be necessary.

Floods won't kill these old classics . . .

The biggest killer of late model cars is corrosion of the electrical systems.  A secondary problem is corrosion of the bodies, engines, and metal parts.   Those things seldom kill vintage cars.

Newer cars are filled with computers and multi-wire harnesses that are ruined the moment corrosion starts to bridge the gaps between pins and circuits – often just a few thousandths of an inch.  Sensor readings go awry, and systems fail.  Insurance companies have learned through hard experience that flooded electrical systems can seldom be fixed to stay, particularly if they have sat for a while.

If you own a vintage car that has seen flooding you will be glad to hear that the same isn’t necessarily true for your car.  Older cars have bigger and more rugged switches that are less likely to be damaged by a little water (or a lot of water, for that matter.)   Old cars don’t have computers, and their wiring is simple enough that we can take it apart and clean it.

In a new car the alternators, starters, window motors and other electrical bits are not serviceable.  They are replaceable.  The problem is cost.  Replacing every electric motor and sensor in the most basic Toyota will cost thousands.  Doing the same in a Mercedes S-Class will cost tens of thousands. 

Old cars are totally different.  We can dismantle and clean every motor and switch in a sixties car and the parts bill probably won’t be but a few hundred dollars.  We may need a week’s worth of time but we CAN do it, and the job will last.  Older cars are far more repairable than the cars of today.

Where a new car may have a $2,000 instrument cluster old cars tend to have individual gauges.  Even when water damaged they are almost always repairable at comparatively modest cost.

Old cars tend to have much simpler interiors, which means it’s a lot easier to strip everything out and dry it after a flood.  The quicker you do that, the better.

Old cars are just as vulnerable as new cars to water getting in the engine.  If the motor floods in a 1957 Jaguar it should be pulled apart and overhauled if it's sat more than a week or two.  The difference is, that job will probably cost ½ to 1/3 what it will cost on a 2017 Jaguar.

Furthermore, the 2017 Jaguar has thousands of dollars of ancillary parts on the engine that will be ruined by flooding.  Motorized intakes.  Electronic fuel injectors.  Alternators.  Sensors.  Each piece hundreds of dollars and dozens of them.  Those parts do not exist on the vintage cars, and that makes the job of flood recovery possible.

What about the interior?  I’ve seen quite a few antique car interiors – especially the wool cloth and velour ones – come through fresh water flooding with very little damage.   We clean them with an extraction cleaner and they are fine.   When interiors are damaged they can be repaired with upholstery techniques that are timeless, where the interiors of new cars must be replaced with expensive factory-made pieces.

If you own a vintage car that is in a flood remember time is of the essence.  If your engine was filled with water last week, we can probably flush it out and get it running next week with no major repairs.  Wait three months and you’ll be looking at an overhaul.

Another thing – if your old car goes into water, DO NOT just start it up (or try to)  If there is water in the intake and you draw it into the cylinders you will break rods and pistons.  If water gets into an automatic transmission it’s instant ruin to put it in drive running.  Yet those systems can be drained, flushed and put back in service with no lasting damage, if done right.

Remember that floods don’t always come from storms or snowmelts.  Your vintage convertible can sustain just as much damage with the top down in a summer thunderstorm.  The thing to remember is this:  Comprehensive insurance usually covers all sorts of water damage, even if you did something dumb.  Just be truthful with the insurance company.  It’s no crime, forgetting to close a window or a roof.

Some vintage cars are even prepared for flooding.  For example, we restore old Land Rovers, Land Cruisers, and Jeeps for people on the Cape and Islands.  Many of those cars spend time on the beach and for various reasons, some of them end up in the surf.  We’ve devised a number of strategies to minimize the impact of what may in that case be “inevitable flooding.”

We use saltwater-rated marine electrical connections, and seal all the wire junctions with liquid electrical tape.  We paint or finish insides of panels and pieces to prevent corrosion if they get wet.  We replace automotive cloth seat covers with marine fabrics like Sunbrella and we use marine grade wood and foam underlays.  Everywhere we can, we treat with Waxoyl corrosion protection and/or POR15 paint.

Stainless hardware now holds this body in place, rather than the original bare steel
Everything is painted or plated, and after this photo was shot, covered in Waxoyl

Sometimes people balk at the cost of that, but the money spent for a beach car may be repaid ten times over during the next ten years.  We can’t eliminate corrosion but we can sure slow it down.

The simplicity of vintage cars makes it practical to repair them after most floods.  Their rarity and value makes the effort worthwhile.

© 2017 John Elder Robison

John Elder Robison is the general manager of J E Robison Service Company, celebrating 30 years of independent Bentley, Rolls-Royce, BMW/MINI, Mercedes, and Land Rover restoration and repair in Springfield, Massachusetts.  John is a longtime technical consultant to the car clubs, and he’s owned and restored many fine British and German motorcars.  Find him online at or in the real world at 413-785-1665

Reading this article will make you smarter, especially when it comes to car stuff.  So it's good for you.  But don't take that too far - printing and eating it will probably make you sick.