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Discussion Starter · #1 ·
Hello Friends. The brake pedal on my '69 Shadow has what I interpret to be excessive travel. The rotors are good as are the pads. Please help me understand why the pedal travel might be excessive. Thank you. -rick, in Houston
 

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You may not have excessive travel. (Of course, you also might, since yours is an early car and there's a master cylinder on yours.)

The brake pedal on the Shadows (and derivatives) is not like that on any other car you have probably driven. It will, whether the car is running or off, always freely travel from its resting point to the floor (or very nearly to the floor) with minimal pressure. Unlike in most other cars, where the brake pedal is intimately involved with the pressure creation process, this one serves pretty much as an open/close valve that allows pressurized fluid to flow from the accumulator to the brakes. It doesn't really have conventional brake pedal "feel" either.

If your brake pressure system 1 and system 2 lights are extinguished and remain that way, and your car seems to be stopping as it should when you apply the brakes, you're probably fine.

You should definitely do the "brake pedal hydraulic system test" that I documented in another thread on this particular forum about two years ago. You need to be certain that you do not have weak accumulators since they're your only source of brake pressure in the event of a stall. No one wants to have a stall and then find that it's impossible to bring the car to a quick and safe stop.
 

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Discussion Starter · #3 ·
Thank you Brian. My 'low pedal' quote came from the dealer where the car is consigned. I have not yet driven the car. I have restored MANY cars and have a nice collection of classics but this is my first Rolls-Royce. I have a lot to learn.

Thank you for your sage advice.

-rick
 

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I am surprised that nobody has mentioned the problems associated with the master-cylinder system installed on early Shadows. The "Pedal going to the floor" symptom is because the master-cylinder circuit, for some reason, on some cars, gets air in it. The result is "PANIC!". It happened to me (Bentley T ser no 10630) twice. Both times the brakes worked Ok when pedal went right down because the two pressure-fed systems are operated by the pedal mechanism at full travel even without the master-cylinder. The second time I did what RR did and removed the master-cylinder system entirely (the master-cylinder was fitted to only early Shadows).

The basics are (A) remove the MC and replace the "FEEL" with a rubber bumper instead and (B) connect the large rear brake pistons to the circuit which includes the G-valve, and the small rear brake pistons to the other power circuit (i.e. swap them over). The rubber thingy gives a little sponginess to the brake pedal to allow one to get used to the brakes being operated by pressure only, not by movement. That was the characteristic of the Citroen 'D' series which took some getting used to.
 

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If your brake pedal is going to the floor, you have a MC issue. Removing the MC from the system is not fixing the MC.
 

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Alan, this issue has been discussed many times in the past in other posts. Perhaps you did not notice but the post above that you replied to was from 2010.
 

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Jim, yes you are right - I saw August 21 and looked no further. Stupid me.

Wraithman, Removing the MC is Rolls Royce's solution, not mine.

Alan D.
 

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Your post wasn't clear and assumed it was yours since no "quote" was referenced and you used the word I in the last sentence of your first paragraph, so reading it gives the impression you did a modification.
Thanks for clearing that up.
The MC was eventually deleted by the factory.
 
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