Spearos Posted May 4, 2013 Share Posted May 4, 2013 A little while ago I replaced the front discs and pads on my 90, at the same time I fitted some rebuilt calipers. All appeared fine, however on a couple of occassions the pedal felt like it went down further with the brakes feeling less effective. If I released the brake pedal and pressed again it did feel better/firmer. Bled brakes, practically no air came out. Checked for leaks with SWMBO pressing on the pedal, I have also monitored the reservoir level and it hasn't dropped. The flexi hoses are not 'bulging' under pressure The rear drum brakes are adjusted correctly. There is no play in the wheel bearings. Pressing on the pedal and starting the engine results in the pedal dropping slightly - servo ok? Discs and Pads are Mintex items and calipers were rebuilt with stainless pistons and genuine seals. For obvious reasons I am a little concerned about this. I'm starting to suspect the master cylinder, but wanted to get some opinions on this? Would a failing master cylinder seal mean loss of brake fluid? Reading the 'how to' article on here about overhauling the master cylinder, it is recommended to go for a genuine kit. However, I see a TRW/Lucas Master Cylinder is around £60 and with a genuine overhaul kit coming in at almost £40 (http://www.brit-car.co.uk/product.php/90765/5497/brake_master_cyl_o_haul_kit_def) I guess I would be better off just buying the Master Cylinder? Quote Link to comment Share on other sites More sharing options...
bear Posted May 11, 2013 Share Posted May 11, 2013 Might the new pads need time to bed in? Griff Quote Link to comment Share on other sites More sharing options...
Eightpot Posted May 11, 2013 Share Posted May 11, 2013 Could be master cylinder - the seals inside might have picked up a little damage if you bled the brakes by pumping the pedal rather than using a vacuum or pressure bleeder. Could be caused by a slight ridge on the cylinder where the pushrod normally goes back and forth - going beyond this when pumping the pedal may damage an old seal very slightly Quote Link to comment Share on other sites More sharing options...
Spearos Posted May 12, 2013 Author Share Posted May 12, 2013 Could be master cylinder - the seals inside might have picked up a little damage if you bled the brakes by pumping the pedal rather than using a vacuum or pressure bleeder.Could be caused by a slight ridge on the cylinder where the pushrod normally goes back and forth - going beyond this when pumping the pedal may damage an old seal very slightly I did indeed bleed the brakes by pumping the pedal, so perhaps you are on to something there. So what do you folks think is best - rebuild the 'Girling' master cylinder with genuine bits? Or, spend about £25 more and buy a brand new TRW master cylinder? Quote Link to comment Share on other sites More sharing options...
Team Idris Posted May 12, 2013 Share Posted May 12, 2013 If you change the seals you don't fix the wear, hence the very small hones that are available. So I'll say new over re-built. And ASAP by the sound of it! I wouldn't run it on a public road incase it gives out. Quote Link to comment Share on other sites More sharing options...
Eightpot Posted May 12, 2013 Share Posted May 12, 2013 Definitely a new master cylinder, the bores do get worn and there may also be bits of corrosion and debris in the ends of the bores - put a new seal in, pump the pedal to bleed the brakes again and you're back to square one. If you do fit a new master you need to bench bleed it first or get the car on an angle to get all the air out - plenty of info on the web. Quote Link to comment Share on other sites More sharing options...
Spearos Posted May 12, 2013 Author Share Posted May 12, 2013 Feel a little foolish now - putting new seal(s) in a worn cylinder would be a really stupid idea! A new master cylinder it is then! Thanks all! Quote Link to comment Share on other sites More sharing options...
Spearos Posted June 13, 2013 Author Share Posted June 13, 2013 Quick update - new master cylinder seems to have sorted it. Predictable braking is back! Got myself an eezi bleed kit and I'm impressed but was wondering do you guys clean/flush out the kit after use? Quote Link to comment Share on other sites More sharing options...
Team Idris Posted June 14, 2013 Share Posted June 14, 2013 Shouldn't have too, but I would, with water. Then I'd dry it and leave it with rag in there to soak up any oil. Putting water in there isn't good, (bad in fact) but I wouldn't expect a new one to be as good as one from 20 year ago, when you could put all sorts into plastic A big syringe worked well to suck the oil through. I tried it for the first time the other day, as recommended on here. Quote Link to comment Share on other sites More sharing options...
mmgemini Posted June 14, 2013 Share Posted June 14, 2013 Clean a Eezi-Bleed ? Mine just gets emptied and put away. Hhh ? I wonder where it is just now Quote Link to comment Share on other sites More sharing options...
cluffy Posted June 17, 2013 Share Posted June 17, 2013 I have had the same as this, never solved the problem. Put disco axles on and it didnt change so that confirmed that it wasnt 1 of the 3 pairs of calipers I rebuilt. Took truck to spray shop went to pick it up yesterday and master cylinder is empty. Must be a very tiny leak I preaume if fluid goes out airxcan go in? It has new master new servo new calipers and pads cleaned out the G valve thing that sits on the chassis under master. That was full of gunk and the ball didnt move. Going to put some fluid in and leave for a few days, I hear spraying deodorant can show you where a small leak of oil is as it has chalk in it. Another useless bit of infomation that came in handy in the Sahara to find a leak Quote Link to comment Share on other sites More sharing options...
Aragorn Posted June 17, 2013 Share Posted June 17, 2013 if its emptied the reservoir thats hardly a small leak! Quote Link to comment Share on other sites More sharing options...
cluffy Posted June 17, 2013 Share Posted June 17, 2013 well the old girl has been sat for nearly a month and theres still a fraction left in the bottom so neither is it a fast leak! ok ill rephrase it all.... it has a medium speed leak Quote Link to comment Share on other sites More sharing options...
Snagger Posted June 18, 2013 Share Posted June 18, 2013 To drain a complete reservoir without driving over just a month, that's a pretty significant leak. At least it should be easy to find if the underside is reasonably clean. Quote Link to comment Share on other sites More sharing options...
cluffy Posted June 18, 2013 Share Posted June 18, 2013 Underside of my landrover clean... chances of that are fairly slim.i have a had a look at all callipera when I changed wheels after respray and could not see any signs of leaks... dont thik there is any fluid to leak out any more. I tjough the master cylinder was splir for front and back but matbe new ones are not thw same? I will see tommorow. Going to buy a eazi bleed now Quote Link to comment Share on other sites More sharing options...
Snagger Posted June 19, 2013 Share Posted June 19, 2013 The master could be leaking into the servo drum, if you're certain that there are no visible leaks anywhere on the system. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.