silver shadow 2 brake problem - Rolls-Royce and Bentley Forums
 
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post #1 of 5 (permalink) Old 07-26-2010, 03:43 AM Thread Starter
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silver shadow 2 brake problem

Hi,
I just signed up to ask for advice about a problem my dad has with his silver shadow 2. Basically, the brakes don't work, the pedal goes to the floor without resistance, and there's no braking at all. There's no fluid loss, but a slight seepage on the distribution valves, and brake warning lights 1 and 2 are on.

He'd like to know how to bleed the complete brake system, if that would help solve it, but any advice you can give would be appreciated.

Thanks in advance.
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post #2 of 5 (permalink) Old 07-26-2010, 12:50 PM
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First, do yourself a favor and go to the Hydraulics Pages on Marinus Rijkers' Silver Shadow Website and read through them and watch the animations. It's really critical that you understand how the system as a whole works (although you could ignore the height control part for the time being).

There is no real "brake feel" on the pedal of a Rolls-Royce other than what's provided by the return spring. All applying the brake does is to open a valve.

If he's got no pressure right off the bat for both systems and it never accumulates then I'd suspect failure of both brake pumps, but this seems to be a highly improbable circumstance.

Search for posts I've made in the past. I believe I put up the fairly comprehensive set of diagnostic steps to help you to determine where the failure in the hydraulic/braking system might be.

Since you're dealing with a Shadow II bleeding the braking system should be quite easy. There is no master cylinder to worry about and the way this system works it's constantly supplying its own pressure. Download my easy brake flush and bleed instructions for further guidance.

Afterthought: When is the last time the brake reservoir was opened and examined? When was the last time for a full system flush and fill? Is the car using RR363 only? You could have tons of crud in the reservoir blocking the filter screens (or worse, the filter screens could have collapsed and the crud is now clogging the gravity feeds to the pumps). These cars need to have their brake/hydraulic system completely flushed & filled once every two years, at a minimum. Many were/are sadly neglected in this respect, and when you take the reservoir lid off and the baffles out you might be shocked what you find. These cars are designed to run only using RR363 fluid (though there are some using DOT3/DOT4 spiked with castor oil, but we won't go there). If the wrong fluid was being used, particularly straight DOT3 it can and will eventually cause excessive pump wear and failure. If, heaven forbid, someone put the later mineral oil hydraulic fluid into an RR363 system, and this has happened, the results are disasterous, with the mixture of fluids turning gelatinous and fouling the whole system.

Brian

The opposite of a correct statement is a false statement. But the opposite of a profound truth may well be another profound truth.
~ Niels Bohr


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post #3 of 5 (permalink) Old 07-27-2010, 02:08 PM Thread Starter
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Thanks for the advice, the car was apparently in storage for years before Dad got it, he's already started flushing out the system so I've printed off your post and that .pdf along with a few other things.
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post #4 of 5 (permalink) Old 07-28-2010, 11:08 AM
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Your observation, "the car was apparently in storage for years," is a huge red flag. One of the worst things for these cars (or any car, for that matter, but the problem range is wider for PMCs [Proper Motor Cars - a commonly used, in an arch (adj, sense 2B) way, colloquialism for Rolls-Royce and Bentley automobiles, taken as offensive by some but playful by many]) is sitting and not being used. So many things just die, freeze, corrode, rot, etc., from lack of use.

The first thing he needs to do is to examine the contents of the reservoir. The next thing is to examine the contents (and hope there are none) of the gravity feed lines, including the metal sections, between the reservoir and the pumps.

My guess is that there is a complete starvation of brake fluid. This is extremely damaging to the pumps if the car is running without fluid getting to them, as the fluid is the only lubricant for the pumps and they are machined to very, very fine tolerances. Running them dry is a recipe for destruction.

Brian

The opposite of a correct statement is a false statement. But the opposite of a profound truth may well be another profound truth.
~ Niels Bohr


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post #5 of 5 (permalink) Old 08-01-2010, 03:40 AM Thread Starter
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Looks like you were right. I showed Dad your post and it matches with what he's found so far. I'm paraphrasing his reply here:

First of all, many thanks for the information, it's helped a lot. There was sediment in the resevoir, that's now been cleaned out. There may have been a blockage. The pipes from the pumps to the accumulators have been taken off, fluid was coming out of the front pump but not the back. After cleaning everything out, the gravity feed lines are now clear (not sure if they were before or not), but there's still no fluid coming out of the back pump.

He's just trying to take the back pump off now, but having difficulty. I'm going to take a look at that site you recommended to try and find some diagrams for it.
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