Wednesday, November 27, 2013

Fixing Power Steering leaks in Rolls Royce and Bentley

One of the most common problems on cars is leakage.  If we can say one thing for sure, when it comes to leaks, it is this:  The higher quality the car, the greater the variety and quantity of fluids it will have to leak.  And all of them will be top grade.  If the car was built in England, its pedigree ensures that every one of those premium liquids will eventually find a path to the ground beneath the car.

While the variety of fluids that can leak may seem infinite, this post will address just one, from one kind of car:  Power steering leakage in 1990-newer Crewe built Rolls Royce and Bentley motorcars.

We see two main sources of steering leakage in these fine cars.  The first is the rack itself, which tends to leak from the input shaft seal and the bellows at either end.  The input shafts leak when dirt works its way down the shaft and ruins the seal.  The bellows leak when the bushings that guide the rack wear, and the rack begins moving more than what the seals can contain.

Here you see dry lines and wetness from the rack seals

Wet rack bellows are a sure sign of bushing and seal failure

The drip below my finger comes from the input shaft seal (above, out of photo)

Looking at the photos you see a typical scenario.  The lines into the rack in the top photo (the most common leak source on many lesser cars) are dry.  The yellow paint on the lines in this photo mark the lines and rack as original to the car. 

The rack is the only leak on this 1996 Bentley undercarriage
This rack is dripping from the input, and the output bellows.  As the photo below shows, it’s the only wet thing on an otherwise remarkably dry undercarriage.  It veritably cries out for repair!

So what do you do?

Your first thought might be to simply buy a new rack. If only you could!  At this moment Bentley’s ability to supply factory-rebuilt or new racks is limited.  When new racks are available costs are generally around $3,000 – more than many owners wish to pay for a part that history shows may be worn out and leaking in 15,000 miles.   Simple resealing of the racks is not usually a long-term fix because of the bushing wear, which happens amazingly fast on some cars.  We suspect the most vulnerable cars are those that run fast on rough roads, for that sort of driving puts the maximum stress on the big bushings in the rack.  We think they get pounded from round to oval, and once that happens, leakage is inevitable.

We’ve been sending our racks to specialist rebuilders with good success.  They change the bushings and seals, and set the clearances.  The body of the rack and the big gear pieces seem pretty indestructible. 

The next problem area is the steering fluid reservoir.  It’s a simple plastic affair located right next to the engine oil filler.  On most cars a plastic reservoir like this would be a $100 part (or less) but Bentley seems to see the situation differently.  When they ran out of cheap (figuratively and literally) molded plastic parts they commissioned the production of Professional Grade stainless steel reservoirs.  At a cost of $1,200.  Yes, you read that right.  Over one thousand dollars for a container that holds a cup of steering oil.

Leaky reservoir removed from the car.  This one was glued, unsuccessfully.  Don't waste your time.
Even in the rarefied world of Rolls Royce owners balk at things like that.  But what can you do?  We have a solution.

Old reservoir and our replacement side by side

The new reservoir in hand.  It's made from the finest molded foam plastic

Setting the reservoir in place

The finished installation looks totally stock, and works better

We have adapted the common plastic reservoir used by Land Rover, Porsche, and BMW to fit our beloved RR/B motorcars.  We modify the original mounting bracket and with a few hours fitting it looks like the car was made that way. 

In the spirit of Thanksgiving (which is about to happen, as I write this post) I'd like to take this opportunity to thank all the discerning motorists who have chosen our company to care for their cars over the years. It's people like you (you know who you are) that make it possible for us to make these discoveries, and devise fixes like you see here.  It's what separates simple repair from craftsmanship, and it's what our crew does best.


John Elder Robison is the general manager of J E Robison Service Company, independent Rolls Royce and Bentley specialists in Springfield, Massachusetts.  John is a longtime technical consultant to the RROC and he’s owned and restored many of these fine vehicles.  Find him online at www.robisonservice.com or in the real world at 413-785-1665.

1 comment:

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