moodoo Posted February 28, 2016 Share Posted February 28, 2016 Guys, hope you can help. Brakes on my car were always very good, but the master cylinder and the servo looked dreadful, thanks to what must have been a longterm fluid leak before I got the car. So much so, that when I took it all apart, there was a load of fluid in the servo! I bought a brand new, ate, master cylinder, removed the servo to give it a lick of paint, and put it all back together. The brakes bled up fine, and I have a good firm pedal when the car isn't running. No visible fluid leaks anywhere now. When I start the car though, the pedal goes really soft. I don't think its air in the system, because the pedal doesn't get any firmer when the car is running, no matter how much I pump the pedal. I also bled the brakes again, just to be sure, and saw no air. If I run the car, turn it off, and quickly disconnect the servo vacuum hose, I hear a rush of air, so I think the servo is making vacuum ok. It should do, it worked perfectly before I took it off the car. I don't know if it's related, but the brake light switch is also on all the time now unless I put my foot under the pedal to pull it back up. This wasn't the case before I started this job. I presume the two are connected, just can't figure out how, or what it means. Thanks in advance for all suggestions and advice! Fin Quote Link to comment Share on other sites More sharing options...
upk Posted February 28, 2016 Share Posted February 28, 2016 Are you sure it was like for like master cylinder? Quote Link to comment Share on other sites More sharing options...
moodoo Posted February 28, 2016 Author Share Posted February 28, 2016 I believe the old one was standard, at least the one I put in was a standard one, I can dig out the ATE number I bought somewhere. The one I took out was so badly corroded on the exterior I can't make out any marks or anything. To know for sure I would have to take it apart, which I'm sort of reluctant to do. Would any external dimensions give a clue as to its size? Quote Link to comment Share on other sites More sharing options...
wayne ingham Posted February 28, 2016 Share Posted February 28, 2016 If you have rubber hoses on you can blank all 4 off and try the padel ,lt OK remove one clamp at a time.this well tell you if the is a fault on that line Is the bore of the new clylinder the same size,But if you are Geting a good brake padal engine not running this may not apply. just a thought Quote Link to comment Share on other sites More sharing options...
Kevin Abbott Posted February 28, 2016 Share Posted February 28, 2016 Sounds like a servo problem or one way valve in the servo line. Quote Link to comment Share on other sites More sharing options...
moodoo Posted February 28, 2016 Author Share Posted February 28, 2016 Thanks for the idea guys. The servo was working 100% before I took it out, is there anyway I could have damaged it or the valve? I only took the servo out, wire brushed it down, and painted. If the servo was damaged, I thought that I would have a pedal that was too hard (ie not enough servo assist), rather than one that was too soft? Is there any way to test it? Quote Link to comment Share on other sites More sharing options...
Scribe of Lincoln Posted February 29, 2016 Share Posted February 29, 2016 This happened to me a couple of years ago. Same issue with loss of brakes and fluid escaping into the servo. I installed a new master cylinder and replaced the servo hose, however within a week the new cylinder was found to be leaking into the servo. It was a new (old) part and I think that the seals had hardened during the years it had been on the shelf. We took the servo out again and replaced the seals with new ones from Bigg Red (Worcester) and problem solved! Quote Link to comment Share on other sites More sharing options...
moodoo Posted February 29, 2016 Author Share Posted February 29, 2016 Thanks....funny, my brakes were fine even with a servo full of fluid, and a master cylinder that looked like a rusty pipe, but now I have a brand new, new stock, ATE cylinder, I have problems! Is there anything I should have done with the master cylinder before I installed it? I see mention on the internet of 'bench bleeding'. I just gave the brake pedal loads of short fast movements until I stopped seeing bubbles coming back into the fluid. Then I bled normally. Twice. Like I say, the pedal doesn't get any harder no matter how much I pump, so I don't think it's air, but it would be the obvious suspect. Quote Link to comment Share on other sites More sharing options...
upk Posted February 29, 2016 Share Posted February 29, 2016 Why does pedal not fully return? What's changed from before that could influence this??? if not fully returning your not getting full travel! kev Quote Link to comment Share on other sites More sharing options...
Exclusive Opel Posted February 29, 2016 Share Posted February 29, 2016 Was the clevis link on the servo push rod accindently screwed in or out? Quote Link to comment Share on other sites More sharing options...
moodoo Posted March 29, 2016 Author Share Posted March 29, 2016 Thanks for the suggestions guys, but it turned out to be something very simple...just for the benefit of the next guy who has this issue, and comes across this thread... Turned out the problem was that the little eccentric washer thingy in the brake pedel had got rotated when I was disconnecting, or connecting the servo to brake pedal. This meant that there was too much play in the system, which is also why the brake light switch wasn't being activated, the eccentric was at a point where it wasn't letting the master cylinder force the brake pedal back strongly enough. It all felt OK without the servo on, but with the sevo activated, I was getting basicaly way too much play in the pedal before the master cylinder started to really work. I didn't even know there was a little eccentric in the brake pedal! I maybe should have mentioned this was on an A-series, maybe As and Bs are different? Anyway, hope this maybe helps someone someday.... Quote Link to comment Share on other sites More sharing options...
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