keithjh Posted June 17, 2012 Share Posted June 17, 2012 Hi All, Need some help ideas here. Brakes will not bleed. HISTORY 1988 110 F reg changed from 2.5na to 300 tdi. Replaced all flexi pipes with Goodrich braided flexis Replaced front brake pipes, replaced pistons and seals in calipers, (genuine LR) Rear brakes adjusted correctly(Drums) Bled the system 3 times, no dirty brake fluid left in system, there was plenty but its now clean when bleeding. If i pump the pedal several times i get a fantastic pedal, release pedal and its back down to the floor after about 5 seconds. With the pedal pumped up and held i have checked all unions etc no sign of any leaks, there are no signs of the master cylinder leaking down the bulkhead wtc. The vehicle has been stood for several months (though run up and moved at times) but up till last week the brakes were fine I am starting to think the master cylinder has given up, but would appreciate any ideas solutions etc Thanks in advance Keith Quote Link to comment Share on other sites More sharing options...
Puffernutter Posted June 17, 2012 Share Posted June 17, 2012 When this happened to me it was a snail cam on the rear brakes that fooled me for quite a while. It seemed to adjust OK, but in reality wasn't. Cheers Peter Quote Link to comment Share on other sites More sharing options...
Maverik Posted June 17, 2012 Share Posted June 17, 2012 My vote is the Master cylinder, had similar on 3 vehicles now, - just replaced the master on my disco re-build, do the brakes "work" right at the bottom of the pedal stroke without pumping? -if so the front piston in the master is bypassing thus the rear piston has to engage both front and back calipers which it shouldn't have to do. Mav Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted June 17, 2012 Share Posted June 17, 2012 Clamp the rear brake hose and try it. Chances are it's the rears that are causing it as above, unless it's a sticky piston on the front brakes. Quote Link to comment Share on other sites More sharing options...
keithjh Posted June 17, 2012 Author Share Posted June 17, 2012 Clamp the rear brake hose and try it. Chances are it's the rears that are causing it as above, unless it's a sticky piston on the front brakes. Unable to clamp goodrich braided hose i think? Keith Quote Link to comment Share on other sites More sharing options...
Retroanaconda Posted June 17, 2012 Share Posted June 17, 2012 Yeah, that's a good point. In that case take the drums and shoes off and put a G-clamp over each wheel cylinder to isolate the rear brakes. If the symptoms go away then the issue is with the rear shoe adjustment. Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted June 17, 2012 Share Posted June 17, 2012 you've refited the calipers to the correct sides havnt you? Quote Link to comment Share on other sites More sharing options...
western Posted June 17, 2012 Share Posted June 17, 2012 you've refited the calipers to the correct sides havnt you? bleed screws at the top, otherwise you'll never get good brakes. Quote Link to comment Share on other sites More sharing options...
jbs Posted June 18, 2012 Share Posted June 18, 2012 Unable to clamp goodrich braided hose i think? Keith What about blanking off the hose with a capped off union so that you can do the same test without clamping it? as in using a blanked off union as a stopper? John Quote Link to comment Share on other sites More sharing options...
Maverik Posted June 18, 2012 Share Posted June 18, 2012 Snail cam adjustment is lack of top end firmness in the pedal, air locks are spongy, its not an air lock, as it pumps up ok, but then slowly releases... which is oil bi-passing a seal, if there isn't any leaks external then its an internal leak in the master cyclinder, get one ordered Mav Quote Link to comment Share on other sites More sharing options...
western Posted June 18, 2012 Share Posted June 18, 2012 are the rear shoes fitted correctly ? Quote Link to comment Share on other sites More sharing options...
keithjh Posted June 19, 2012 Author Share Posted June 19, 2012 bleed screws at the top, otherwise you'll never get good brakes. I`m a PLONKER Thats me!!! All sorted thanks Regards Keith Quote Link to comment Share on other sites More sharing options...
Maverik Posted June 19, 2012 Share Posted June 19, 2012 Snail cam adjustment is lack of top end firmness in the pedal, air locks are spongy, its not an air lock, as it pumps up ok, but then slowly releases... which is oil bi-passing a seal, if there isn't any leaks external then its an internal leak in the master cyclinder, get one ordered. Mav Ok next time it will be your master cyclinder... glad you've found the problem... Quote Link to comment Share on other sites More sharing options...
western Posted June 19, 2012 Share Posted June 19, 2012 I`m a PLONKER Thats me!!! All sorted thanks Regards Keith well at least we found the problem & it hasn't cost you any more cash. Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted June 19, 2012 Share Posted June 19, 2012 I've done it and a few of my friends have... Easy simple fix, just what we like. Quote Link to comment Share on other sites More sharing options...
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