Bricol Posted March 25, 2010 Share Posted March 25, 2010 Not on the Caterham - on a heavily loaded integrale on the way home today. Been enthusiastically making progress until I came into the home town and joined the queue. In the queue through town, the pedal was low on one press . . hmm . . double pump and back to normal and rock solid. Crawl a bit more - pedal to floor! Several pumps back to normal and solid - two feet, servo assisted press - solid! Quick check reveals lots of fluid in reservoir. Pedal did the same numerous times on the, careful, way home. Having a typical integrale handbrake, progress was . . slow! Each time, another press did something but still low - pulled to right, more presses brought it up square and solid. Inspection when home revealed no leaks to calipers, or indeed anywhere in the visible brake lines, including the ABS pump. And still fluid in the reservoir. So what's happening? I can't imagine the pistons are knocking back so far as to have no pedal at all on a smooth rood at walking pace when there is no wobble through the pedal from the discs. Reservoir is connected to master cylinder with flexible hoses - no leak I can see from underneath - but it could be they are constricted, kinked etc - I still can't see that being a problem as fluid is in the system from master cylinder to calipers. and I can't see them suddenly kinking either. Brakes, good, grooved discs, decent fluid, good name pads, etc - they don't fade, even loaded with trailer etc - and they weren't warm in the queue as there hadn't been much braking on the way. Any suggestions would be appreciated - currently got me stumped. Car is a daily driver (although not now!) and due to recent house move, I can't get it apart easily at the moment - grr! Bri Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted March 25, 2010 Share Posted March 25, 2010 Bulging flexible hose ... about to burst ? 😳 Link to comment Share on other sites More sharing options...
CageyH Posted March 25, 2010 Share Posted March 25, 2010 Internal seals gone/going in the master cylinder? Only dead fish go with the flow....! Link to comment Share on other sites More sharing options...
Domus Posted March 25, 2010 Share Posted March 25, 2010 Seals in master cylinder would be my guess, piston moving but leaking seals not pushing all the fluid. Rapid pumping would build up some pressure, but I could be wrong. Damn must learn to type with two fingers. Edited by - Domus on 25 Mar 2010 20:18:16 Link to comment Share on other sites More sharing options...
Molecular--Bob Posted March 25, 2010 Share Posted March 25, 2010 If its simillar to a renault fault on old Clios, your master cylinder may be leaking into your brake servo due to a faulty seal, hence no leaks, but i would have thought you would see fluid loss from the M/C if that was happening. Edited by - Molecular--Bob on 25 Mar 2010 20:23:28 Link to comment Share on other sites More sharing options...
Bricol Posted March 25, 2010 Author Share Posted March 25, 2010 That's the bit I can't figure - there's no apparent fluid loss as leaking into servo was my thought too. Hoses are braided - so any damage is likely to be hidden at the moment- and would a bulging hose give a soft pedal once some pressure obtained? As for seals at either end of the system, surely the pedal would simply be soft, and would sink, if only slowly, once pressure obtained? Been back out to it and I discovered a puddle under the front n/s - but it's not coming from the brake circuit - it appears to be from the supply hose to the clutch master. But the level in the shared reservoir, which isn't huge, isn't dropping. Pedal now there on first press, and still rock solid. Bri Link to comment Share on other sites More sharing options...
TJG Posted March 25, 2010 Share Posted March 25, 2010 If no wheel bearing play forcing pads back then master cylinder is the likely culprit. Tony Link to comment Share on other sites More sharing options...
6speedmanual Posted March 25, 2010 Share Posted March 25, 2010 M/cyl failure. The internal leak can be from primary to secondary chambers without any external leak. A sharp prod or pumping the pedal spreads the failed seal so it it squashes out to the cylinder wall giving some (inconsistent) recovery. Would expect to find seals either squishy or lip worn flat when cyl stripped. Peter BRAWNGP green SUPERLIGHT FCITW 2009 😬 Link to comment Share on other sites More sharing options...
diggerman Posted March 25, 2010 Share Posted March 25, 2010 Almost certainly an internal leak in the master cylinder. Probably gets worse as the fluid warms. peter Link to comment Share on other sites More sharing options...
I.Mupferit Posted March 26, 2010 Share Posted March 26, 2010 Years ago my old E Class had a similar problem that turned out to be leaking seals in the master cylinder, as others have suggested. Mine wasn't visibly losing fluid either. Link to comment Share on other sites More sharing options...
Bricol Posted March 26, 2010 Author Share Posted March 26, 2010 Bug ger - guess what's a discontinued part on integrale evos ? Must find time this weekend to either remove the engine/drivetrain/front bodywork to get to it, or most of the ABS system . . . Thanks for the suggestions. Bri Link to comment Share on other sites More sharing options...
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