I have a GTD with standard granada brakes and twin servo`s. I am looking to upgrade to Willwood or AP etc but for the time being I have started having trouble with the current system. When I release the brake pedal the brakes seem to stay on for a couple of seconds this happens intermittently. Any ideas?
Sticking brakes
- Thread starter MartinGough
- Start date
How old are the brake line hoses?
Martin, this has been suffered by a number of people including myself. There have been a couple of threads about it. I searched on "servo" and "sticking" and came up with this one. Usually it is a sticking air valve in the servo(s).
Brake seizure thread
There are other threads so try other relevant search words.
I myself refurbished my servos, but it did not clear the problem totally. I was told by the supplier that my servos "were not the normal ones for a GT40 replica" and am changing to servoless brakes.
hope this gets you started
Dave
Brake seizure thread
There are other threads so try other relevant search words.
I myself refurbished my servos, but it did not clear the problem totally. I was told by the supplier that my servos "were not the normal ones for a GT40 replica" and am changing to servoless brakes.
hope this gets you started
Dave
I wouldn`t know if residual valves are fitted. I haven`t a clue where they would be or what they look like.
The brake lines are from 1998 and would appear to be in good condition.
I seem to remember someone mentioned a valve that applies a pressure (5psi I think) to the system. Would this be a residual valve? I am struggling with this one and not really happy driving the car.
Any help is appreciated.
The brake lines are from 1998 and would appear to be in good condition.
I seem to remember someone mentioned a valve that applies a pressure (5psi I think) to the system. Would this be a residual valve? I am struggling with this one and not really happy driving the car.
Any help is appreciated.
Ian Anderson
Lifetime Supporter
If you remove the vacuum line from the servo and plug it.
The servo will now be non operable - need to pump the brake a few times to get rid of remaining vacuum.
If you drive the car the brake pedal will require more pressure to get it to stop - if you release the pedal and the brakes stay on I would then assume somethig else is sticking as opposed to the servo/s
I am not a mechanic and believe this to be the case and it would make sense to me
Worth a try and pretty quick and easy
Ian
The servo will now be non operable - need to pump the brake a few times to get rid of remaining vacuum.
If you drive the car the brake pedal will require more pressure to get it to stop - if you release the pedal and the brakes stay on I would then assume somethig else is sticking as opposed to the servo/s
I am not a mechanic and believe this to be the case and it would make sense to me
Worth a try and pretty quick and easy
Ian
Howard Jones
Supporter
Both ends of the car? If it's only one end then it's the servo more than likely. Both then it's the master. Both it could be the servos but they would both have the same sticking little piston. That is possible and common for at least one to stick from corrosion.
Same symptom as mine Martin? Both ends, intermittent, sometimes front sometimes back. You can jack the car up, operate the brake pedal, then try to turn the wheels by hand to see if they have stuck on. Thats what confirmed it for me. From what I have seen on this forum, the servos seem the most likely of all faults, and therfore the one to check first.
In case it helps, my servos were as follows;
Twin Lockheed Servos
Aluminium tag on both 4257 818 7
On one L46F, on other L48F
Dave
In case it helps, my servos were as follows;
Twin Lockheed Servos
Aluminium tag on both 4257 818 7
On one L46F, on other L48F
Dave
Thanks everyone I will have a go at them tomorrow and see how I get on. The pedal when I have the problem stays up and feels hard to press, if you then leave it it takes a second or two too release. If you quickly dab the pedal this seems to release the pedal pressure immediately.I haven`t had the car long. Is there a nack to jacking the car up, I would hate to crack a screen like on a TVR.
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Sorted. With the help of forum members and a call to a very patient Frank Catt at Wealden Engineering the problem has been solved (fingers crossed) I removed the vacuume diaphragm and the mounting plate on each servo in turn. I gentle tap on the pedal removed the small piston which in one unit was all dirty around the two seals. Both were cleaned and re-installed. Problem solved, up too now at least. Once again a big thank you to all who helped.
Howard Jones
Supporter
Martin, If you let your car set for extended periods of time in cold, humid weather, I 'm thinking about parts of the country where it rains for months during the winter, then I think it would be a good idea to have a look at those little piston before using the car again. Each spring might be a good PM schedule.
Glad you got your problem solved. I had the exact same one after letting all the parts set in boxes during my build. When I first started running the car the brakes seamed to drag intermittently. Same fix.
Glad you got your problem solved. I had the exact same one after letting all the parts set in boxes during my build. When I first started running the car the brakes seamed to drag intermittently. Same fix.
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