Monday, January 19, 2015

When rust spots blossom on rust free collector cars

What do you do when your collector car sprouts rust spots in the middle of the hood – an area that had no previous sign of damage?  If you’re a restorer with an inquisitive mind, you find out why it happened.  That’s what we did when this show-winning 1963 Continental Convertible sprouted a rust bubble in the middle of the hood.

The '63 Lincoln on the show field at Newport, RI
The rust bubble that got the ball rolling
We might not have dug deeply into this, if not for the fact that it had happened before, on the same vehicle.  Two years before we’d painted a rust spot on the hood and chalked it up to paint chipping or “causes unknown.” When a similar spot appeared in a different area we realized something had to be going on.

The something is rust from behind.  And when you look at the “behind” photo of this hood that is hard to believe.  There is no sign of rust on this hood; no sign that it ever had any problems.  But when we matched up the location of the rust spot on the front we found it matched the location of a spot weld where the inner frame was welded to the hood’s outer skin. 

The inner frame of the hood shows the voids where water was trapped
Once we saw that we realized there were probably more trouble spots around the other spot welds.  We removed the hood and stripped the paint to find 20 other incipient rust spots.

The hood, removed and stripped of paint

Little rusts spots were everywhere, hidden under paint

Here’s what happened:  Back in 1963, the folks in the Lincoln assembly plant welded the two pieces of the hood together without any surface treatment.  They used ordinary rust-prone sheet steel.  Once welded together, the hood was painted and sent out into the world.

The process of welding the egg-carton frame structure to the smooth outer hood panel created a number of areas where water could become trapped.  Over the next 50 years that is exactly what happened – every time water hit the underside of the hood a few drops worked their way through the gaps between the outer panel and the frame and they sat in the inner space, where rust began to grow.

It took quite a while, but by ten years ago, rust was starting to eat through the outer panel around the spot welds.  Left unrepaired, the rust would have eventually separated the two panels – sort of a “tear on dotted line” of rusted out spot welds.

All American cars of the 1960s and most foreign cars were made with this same technique. Some cars are still made this way today.  Luckily, most high-end cars today are made with steel that has been treated for corrosion resistance, and seams like these are often sealed after they are welded. Those techniques stop rust like this before it starts but they are no help on this 1963 car.

Studs welded over rust spots

A stud welder in use on a fender (not this Lincoln)

The big question for us was what to do about it.  Our body man came up with an innovative solution to put metal back into those rusted areas.  He used a stud welder to weld studs to the hood panel in all the affected areas.  The stud welder did not warp the sheetmetal of the hood as much as conventional welding, but it still put metal over the damage.  When we were done the hood was bristling with studs, which we ground off flush. 

We drilled into the frame behind the hood and sprayed Waxoyl rust treatment into the cavity.  We hope that will slow the process of corrosion from inside.  Short of cutting the hood apart and remaking it that is the best anyone can do. 

The studs have been ground off and smoothed

The hood, painted and ready to go back on the car
A small amount of glaze was used to level the hood surface as the welder made am impression a few thousandths deep.  Then the repaired panel was primed and refinished (front and back).

We fitted the sound deadening into place and finished the edges.  With a car of this quality we need to have the same finish on the inside that you see on the outside.  They didn’t care too much about that in the Lincoln plant but collectors today look for finish details like those. 

The fender tops are painted sans hood so paint flows into the undressed area smoothly
The assembled car, curing and ready for final buff and polish

With that in mind, we sprayed the tops of the fenders as you see to get an even finish across the top of the car.  Our cars are painted in modern Glasurit finishes and this blending technique is normal with that process.

The repair process you've seen here was used on a Lincoln.  The job would be essentially the same on a Chevrolet or even a Fiat.  We show a repair of a hood but this same assembly technique was used on quarter panels and other parts of car bodies, and these repair techniques apply there too. Rust-throughs at spot weld seams are more common than many people realize.

Experience with work like this is what distinguishes a restoration shop from a modern collision shop. Shops that fix wrecks are accustomed to doing fixed-price work for insurance companies. Rust is much less of a factor, and replacement parts are generally available. The goal of that sort of work is a quick repair that's "good enough" when seen from outside.  Discerning enthusiasts want more, and that's where specialists come in.  Look for lots more attention to detail, and more focus on repair than replacement because new parts are often not a viable option on 50-year-old cars.

In a repair shop, the final paint process may be the same on a 1955 car and a 2015 car, but all the steps leading from the car's arrival in our shop to it's rolling out the door will be different. And the paint process itself may be different as some antique cars are painted in "vintage" paint processes like nitrocellulose lacquer.  It's surprising how different the skill requirements for restoration and collision repair are. The process of finding and fixing all the incipient rust spots, and then finishing everything we touch to a high standard is time consuming.  But if you've got a rare and beautiful car that is what you want.

The finished result is shown below – better than new, and ready for parades and shows in 2015!

Best wishes
John Elder Robison

John Elder Robison is the general manager of J E Robison Service Company, independent restoration and repair specialists in Springfield, Massachusetts.  John is a longtime technical consultant to the RROC and other car clubs, and he’s owned and restored many fine vehicles.  Find him online at or in the real world at 413-785-1665

Monday, December 22, 2014

When Heat Fails Us

This is the time of year when we depend on heat in our cars.  For most of us, the heat delivers on its design promise.  For a few unfortunates, though, it doesn’t.  The mechanic checks the coolant level, and makes sure the thermostat is working as it should.  If the engine is up to temperature the next place to look is the heater control circuitry.  When all else fails we are left with the possibility that the heater core itself has failed.

Heater core replacement is the automotive equivalent of a root canal.  It's ugly, painful, and costly but sometimes it has to be done.

Heater cores are like small radiators that shed some of the engine’s heat into the passenger compartment.  There are two ways a heater core can fail – by leaking or by clogging.  Leaks are obvious because you’ve got coolant all over the floor.  Clogged cores are more subtle.

Take a look at this core from a 2006 Land Rover LR3.  There’s nothing obviously wrong from outside, but when we cut the core open we saw a different story.  The whole far side of the core is clogged.  Only the left side of the core remains open.

You might think that would cause weak heat, but it actually created a different problem. This Land Rover – like many other late model cars – has separate temperature controls for the driver and passenger.  The air that blows through the core is sent to the left and right sides respectively, so with one side clogged we had normal heat on the passenger side, and virtually no heat for the driver.

This seemed like a control problem but it wasn’t.  When heater cores clog the repair is often a big deal.  In this Land Rover the whole dash had to come out for repair, as you see.  Jobs like this can run into multiple days of labor, and cost thousands of dollars.  And this is no place to cut corners looking for a low bid – this is detailed work.  Every fastener left loose, and every broken bracket is a potential rattle.  There are a hundred electrical connections, and any that come loose are problems for tomorrow.  This is work for someone who knows Rovers and specializes in large interior repairs.

When a job like this is done there will be faults in the airbag system and many other dash electronic systems.  The person who does the work will need to have a factory-level test system to clear those faults and ensure everything is working as it should.

 At Robison Service we are proud to be known as experts in repairs like this.  Author John Robison is a long time Land Rover service manager, and a technical advisor to many Rover clubs.  He’s written many articles on Land Rover service – indexed here.

No Land Rovers were harmed in the writing of this story, and environmentally friendly repair methods were used throughout.  We are located in Springfield, Massachusetts, where we stand ready to provide top-quality service and repair to owners of BMW, Jaguar, Land Rover, Mercedes-Benz, Porsche, and Rolls-Royce and Bentley motorcars.

© J E Robison Service

Wednesday, December 3, 2014

An Index to John Robison's Land Rover Service Thoughts

The Supercharged Range Rover (c) J E Robison Service

The ex-Buick V8 that Land Rover sold in America from 1987-2004 was never known for its reliability.  However, things took a sharp turn for the worse in 2002, and the last Discovery engines appear to have been doomed from the start.  Here are three articles about internal problems in the V8s:

V8 engine failures - slipped liners and more - from 2009

Should you rebuild a failed Land Rover motor? I have an article about that situation here that covers the decision process

What's the latest on top hat or flanged liners? This article tells all you want to know about the flanged liner overhaul

Discovery II models also have a problem with frame rust.  We first began to see this in the spring of 2014, when we saw several trucks whose rear frames rusted right through over the winter.  These vehicles seemed more vulnerable to rust than the earlier models.  Read this article to find out why, and what you can do about it.

Are you thinking of restoring a Land Rover?  This article shows some of what's involved.  This article explains the difference between repair and restoration, two very different processes.

If you drive a Range Rover Sport or LR3, read this story on differential failures

And if your supercharged Rover is losing power - read this

Programming keys for your Land Rover is here

(c) J E Robison Service

John Elder Robison is the founder of J E Robison Service, independent Land Rover specialists in Springfield, MA.  John's shop has supported Land Rover owners since 1987. They are experienced at all aspects of service, repair, overhaul and restoration.  Find Robison Service online at or on the phone at 413-785-1665.

Friday, November 28, 2014

Index to Rolls Royce and Bentley tech tips

Bentley Arnage - (c) J E Robison Service

A rare Rolls Royce Corniche S - (c) J E Robison Service

I've written quite a few articles on Rolls Royce and Bentley, and I have begun gathering them together here.  One day I'll probably turn them into a book.  Till then . . . Feel free to comment or offer corrections.

Thoughts on buying a used Rolls Royce or Bentley - applies to Silver Cloud and newer series cars

More thoughts on Spur - Spirit - Turbo era car buying

Thoughts on restoration - applies to all cars

Evolution of the RR/B models - Silver Shadow through Arnage/Seraph - original article from the Robison Service website

Inspecting a Rolls Royce or Bentley - Applies to Corniche, Continental, Azure, Turbo R, Mulsanne, Eight, Turbo R, Silver Spur, Silver Dawn, Silver Spirit

More Things to Look For in a 1981-2000 Rolls Royce or Bentley - this is the original article from the Robison Service website

The last Crewe built Rolls Royce convertibles - applies to 2000-2002 final Series Corniche

Repairing convertible top hydraulics - Applies to 1996-2004 Rolls Royce and Bentley Corniche and Azure cars

Head gasket failures in Bentley Turbo cars - applies to Turbo R, Continental R and T, Azure, Arnage

Checking engines after head gasket failure - Applies to all cars

Checking and inspecting Rolls Royce hydraulic systems - all cars after Silver Cloud and print to Silver Seraph. Applies to all Shadow/Spur era vehicles

Case Study - brake failure in a Shadow - Silver Shadow era cars with RR363

Rear suspension gas springs - Applies to all 1981 - 1999 cars prior to Silver Seraph

Changing batteries in seat and ECUs, Applies to 1980s-1990s Silver Spirit / Silver Spur / Mulsanne /Eight / Turbo R

Changing alarm ECU batteries,  Applies to 1980s-1990s Silver Spirit / Silver Spur / Mulsanne /Eight / Turbo R

Servicing Shadow and Spur series brakes - applies to 1966 - 1999 cars after Silver Cloud and prior to Silver Seraph

Alcon racing brakes for Continental and Azure - Applies to all 1990s cars but most particularly to the final series Azure, which had these brakes fitted at the factory - a unique variant

Fixing Power Steering Leaks - applies to 90s cars with the reservoir above the alternator

Questions and answers on collector car storage - Applies to all cars

Evaluating paint - Applies to all cars

I hope you find these suggestions useful, and I wish you luck and success, keeping your Rolls Royce or Bentley motorcar on the road!

Best wishes

John Elder Robison

John Elder Robison is the general manager of J E Robison Service Company, independent restoration and repair specialists in Springfield, Massachusetts.  John is a longtime technical consultant to the RROC and other car clubs, and he’s owned and restored many fine vehicles.  Find him online at or in the real world at 413-785-1665

Wednesday, November 26, 2014

Convertible Top Repair in Bentley Azure / Rolls Royce Corniche

Convertible top hydraulics are shaping up as a major weakness in the Bentley Azure and Final Series Corniche from Rolls Royce.  These cars were built from 1996-2004 (a newer Bentley variant remains in production today) and all are vulnerable to this issue.

The Bentley Azure and RR Cornice are fine cars but the tops are a weakness (c) J E Robison
Here’s the problem, in a nutshell.

The engineers at Crewe wanted to design a fully automatic convertible top for the new Azure series.  But they did not have the resources to do a new design; they had to adapt something else that was already out there.  The Mercedes SL500-type design was well regarded, and they chose to adapt it to the Azure body.

Unfortunately, the design didn’t work as well on the RR/B.  It’s remarkably reliable on the Mercedes, and astonishingly flimsy and incredibly costly to fix on the Azure.  What went wrong?

There are a few essential problems.  First, the systems use very high hydraulic pressures.  Older automatic tops used big cylinders and rams.  With several square inches of ram, you don’t need very high hydraulic pressures to generate the force to move the top.  However, the newer cars use tiny actuators hidden in the top. They are smaller, so the hydraulic pressure needed for a given actuation force rises.  Because the hydraulics are hidden, they are often at a mechanical disadvantage (leverage in reverse) and need to push harder to move the top.

The result:  hydraulic pressures on a 2001 Bentley convertible top can run almost 10 times as high as the pressures on a 1987 Bentley convertible top.  With that factoid in mind, it should not surprise you that the newer tops are not as reliable.

In addition, the newer tops use automatic latches instead of human power to pull it shut and locked.  Those latches are not as rugged as they should be.  Why, you ask?  Look at a Bentley Azure and then look at an SL500.  What do you see?  The Bentley top is significantly larger.  That multiplies the forces on every component and it’s one more reason a reliable Mercedes design didn’t work out the same on the RR/B.

The next problem probably started in Crewe’s engineering department, though I doubt they would admit it.  Mercedes uses plastic lines that are impervious to hydraulic fluid, but that material selection did not translate to RR/B. Someone there chose a hose material that deteriorated with contact with hydraulic fluid.  The result – when they get to be ten years old you see the black rubber casings falling off the hoses, and blowouts inevitably follow. 

How do you check your convertible top hoses?  Look at the hoses in the main hinge area when the top is partly lowered.  Here are examples of hoses that are coming apart.

The upper photo is a closeup of jacketing peeling from a hydraulic hose.  Failure is imminent (c) J E Robison Service
If this problem is ignored you will see leakage, as evidenced by the leaked oil in these photos.

Leaked hydraulic oil in the convertible top well (c) J E Robison Service
Oil seeping from the convertible top hydraulic line bundle 
If you ignore it even longer, you will eventually be showered with oil when a line blows under pressure and the interior of the car is sprayed and damaged.

Header bar line with deterioration.  These are the worst if they blow
"Green showers" most often come from the header bar, when the lines above the rear view mirror blow out.  The reason those lines are the first to blow is that area takes the most beating from the sun. In a hot climate that area can be over 200 degrees all day, and the oil they originally used breaks down into a green jelly that won't pump, and causes pressure surge and blowouts.  Jaguar is known for having this problem too.

The new hydraulic oils are synthetic and they resist this, but the moral there is - change your top hydraulic fluid every few years, or else.

When the top is partly folded there is another thing you want to check – the cables.  These new automatic tops need to fold into a tight space to be hidden under the rear deck.  To do that they rely on cables sewn into the top lining.  Loops of wire around those cables pull the top fabric against the bows and fold everything properly.  If the cables break the top will jam in the bows, and if the bows bend as a result – you have big trouble.

Broken stay cable on Bentley convertible top
In most of these cars you will see leakage from the hydraulic actuators in addition to problems with the lines.  Here is a set of actuators removed for service.  We rebuild these units rather than replace them.

So how do you fix this?  You remove the trunk lining, and the pump and lines.  Open the convertible top boot and remove the top as an assembly. Remove the cover in the convertible top well, and unthread the lines there.  Remove the rear seat, both side panels, the right side floor covering, and the right side dash and windshield pillar trim.  Remove the windshield header bar covers.  Remove the lines and remaining actuators.  Replace and reassemble.

Sounds easy?  Look for a job time of 60-90 hours, more if you are not experienced or run into trouble.

In the next convertible top installment I will begin to cover the actual repair process.

This article is about the automatic convertible top system used in Rolls Royce and Bentley Azure and Corniche from 1996-2005.  Check out this article for thoughts on the newer Bentley GTC convertible top and its problems

And here's an article on 1997-2005 Jaguar XK8 and XKR convertible tops - they have some of the same issues but are simpler to fix

Good luck
John Elder Robison

Robison Service has provided independent service, repair, and restoration for Rolls Royce -Bentley owners all over New England for over 25 years. Founder John Robison is a long time technical consultant for the Rolls Royce and Bentley Owners Club. Our company is an authorized Bosch Car Service Center. We also service Mercedes, Jaguar, Land Rover, Porsche, and MINI motorcars. We have flatbed transport throughout the northeast region, and we work with Intercity and other transporters for greater distances. We also offer pickup and delivery for cars in  Springfield, Wilbraham, Longmeadow, Agawam, Westfield, Northampton, and Amherst.  Our drivers are available to pick up cars in Boston, Hartford, Greenwich/southern CT, New York, Rhode Island, Vermont and New Hampshire.