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Discussion Starter #1
:)Hello im new to this forum website this is the best RR forum on line.
Yeah so just got this to restore it 1973 Silver Shadow Beautiful color about a month and a half ago too many stuff to write right now what work i did to it, so anyways did the master cylinder for the rear brakes got the original kit from England, and everything went good even clean out the reservoir which was clogged topped of with new DOT3 and Castor oil and all, bleed all the breaks like i was told, clean fluid was coming out.
pump the pedal for rear break the bottom bleeder not the top it went fine and bleed the other rest with the pedal to the floor with car running bleeding pressure is good.
Tested on the side street for like half hour works fine, but the problem i have with the breaks when i try to go on the freeway the rear breaks locked up and the break pedal went up and stiff but i was try to press the hard couple of times and it let go thank God, any one had this problem?:crying
 

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Most likely junk in the "G" valve or the master is not returning to rest all the way. Also, old brake (not break) hoses should be replaced. All the brake components are sensitive to even the smallest junk. Hoses break down internally and as a result the fluid becomes polluted with small rubber and often has a grey color.
Jack the rear under the differential , not the crossmember, and bleed the rear calipers. If it frees the wheels you know there is blockage.
Also the factory service manuals should be read. They explain how everything on the car is serviced.
 

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Discussion Starter #3
Master cylinder Adjustment

Sorry about that missed spelling the brakes it was late last night Wraithman and thanks for your help on this issue. Well the RR has 95,654 miles on it or so and i just got this car to work on, in the past some other mechanic was working on it he did some stuff that i don't like that he did on it, so im right trying to correct the problems which it sucks for me :| but any ways the rear high control doesn't work at all from the previous mechanic. had the master cyl rebuild and it was giving good pressure but one think that i missed i guess i didn't adjust the operation rod on the master cyl, i finally found the right web site for it and the prints are clear, im going to adjust the rod to the specific spec as on the picture. then jack up the rear end bleed and see if they lock up again. One more thing will the rear levering system not working will cause the master brake sys to lock up???:?: I think it has nothing to do with the master brakes
(not sure what is the "G" valve or location, i have the pic of the whole sys)
thank you for your help

https://www.rollsroyceforums.com/forums/members/22314-wraithman.html
 

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Discussion Starter #4
Master cylinder locked up

:)hello im new to this forum website this is the best rr forum on line.
yeah so just got this to restore it 1973 silver shadow beautiful color about a month and a half ago too many stuff to write right now what work i did to it, so anyways did the master cylinder for the rear brakes got the original kit from england, and everything went good even clean out the reservoir which was clogged topped of with new dot3 and castor oil and all, bleed all the breaks like i was told, clean fluid was coming out.
Pump the pedal for rear brakes the bottom bleeder not the top it went fine and bleed the other rest with the pedal to the floor with car running bleeding pressure is good.
Tested on the side street for like half hour works fine, but the problem i have with the breaks when i try to go on the freeway the rear brakes locked up and the break pedal went up and stiff but i was try to press the hard couple of times and it let go thank god, any one had this problem?:crying

sorry about the spelling
 

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Hi Dan, Your situation is very common, ie previous mechanic trying to work on a Rolls and has no clue. You are on the right path coming here for accurate advicea and direction. The G valve controls rear wheel lock-up during sudden braking and is known to hang up with debris because it is in the rear brake circuit. The height control system is part of circuit #2 and is mostly passive unless passengers or a load is in the trunk and triggered into fast mode via the height control solenoid valve letting in hi pressure to compensate for the weight.
Completely separate from both brake circuit but shares the pressure and rear reservoir.
 

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Discussion Starter #7
ok so this seems right that is the g-valve ill try to find it and rebuild it. Here are some pictures of it not sure the right location but i can match it wit the pictures or trace the brake lines on the return to the system.

Thank you sir

(but i should still adjust the master cylinder rod?)
 

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G valve is on the rat trap directly above the master cylinder. Yes you should adjust the master pushrod to have some free play. While you're in there, make sure both of the distribution valves have clearance too and that one is not hanging up. That could be the cause of rear brakes staying on as could collapsed rear flex hoses. They collapse inside and act as one way valves.
 

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Discussion Starter #10
Upate BRAKES

Just an update of this brake situation that im having, so i had some time to check out the problem which i adjusted the master cylinder rod it was in,,, about a quarter of an inch, then i tried to bleed the master brakes to find out that the passenger side break caliper is leaking now, and thats why i have a partial break failed light on, need to rebuild it and get new break pads y any good web site for parts for the Silver Shadow? (And yes all the flex brake lines been change):)
 

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Daniel,


You don't say front or rear passenger side.


I am just rebuilding my spare set of fronts and got stainless steel pistons and rubber kits from our UK supplier Rimmer Bros.


These are same parts/calipers used on a lot of British cars and listed as Triumph calipers. The parts were a lot less than from a RR/B agent too.


Steve
 

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Discussion Starter #14
Sorry about the late reply, but i needed the 2 back once i just rebuild them the other day got new pads and seals, but thanks anyways. ill be posting some pictures later on still trying to bleed them today the passenger side was leaking
 

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Discussion Starter #15
Ok i little update about this Silver Shadow, just some pictures of the calipers, it was time for them for sure and especial when the rear brakes locked up on the free way going maybe 70. they got hot the rotors are still good to a point, just want the breaks to work wright. any ways i try to bleed them master cylinder but did work out to good so i went under the car and like i was said to inspect the G Valve. it was a little pain to take the sucker out lol, that retaining plug screw was rusted on pretty good but i have the Milwaukee impact gun so maybe like 3 times got it free. then i empty out the steel ball and spacer plate, didn't look too good at the bottom of the valve body, i clean it out and to find out the seal look ripped up so my question to you professional guys on here can i get a new seal?? and where, if not ill have to wait another week for this g valve body :), what i mean also it looks bad and looks different then a regular,, i looks like a tiny tire lol any ideas for me?
PS IF THEY REBUILD THEM where do they get them lol thanks guys here is some pictures of this disaster. thank you for reading my post
 

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Daniel,


Those brake pistons are pretty bad....I hoped you replaced those as well as the seals.


The G valve rubbers/kit were available at Introcar in the UK but currently out of stock. The whole unit can be bought from Flying Spares as a reconditioned part so service parts are available.



Hopefully Brian (Guyslp) or Wraithman will read the thread as they seem to know a lot of the altenative parts and US suppliers as I doubt this part was bespoke to the RR/B.


All the best


Steve
 

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The rust spots, unless polished out or replaced with stainless pistons, may give you problems with the pistons retracting. If they cannot retract easily (very small amount) you run the risk of pad to disc engagement creating heat and premature wear.

I would send out the G valve as an exchange if no rebuild kits are available.
 
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