mr vigton Posted March 3, 2014 Share Posted March 3, 2014 I changed the front pads on my acclaim (I have done this before many times including on this actual car) when I went to test drive it the brake pedal bounces up and down under braking!? But why? Fairly certain I never damaged anything whilst changing them and followed normal procedures as per manuals, any ideas why this has happened? Quote Link to comment Share on other sites More sharing options...
Toledo Man Posted March 4, 2014 Share Posted March 4, 2014 The pads need to bed in so they match the profile of the disc. It typically take a couple of hundred miles for them to bed in and be gentle with the brakes while you bed the pads in.When you changed the pads, did you take the top off the brake fluid reservoir? This will allow the level to rise when the pistons in the calliper are pushed back in. Did you use copper grease on the back of the pads where they come into contact with the callipers? This will help to stop squealing. You also need to put copper grease on the bolts so that the calliper moves freely. When I change the pads I press the brake pedal after I've done each side to push the pistons back out. Have you forgotten to do this? Quote Link to comment Share on other sites More sharing options...
mr vigton Posted March 4, 2014 Author Share Posted March 4, 2014 Yes I did all of those things as you described. I guess the discs must be worn and new pads have made the problem worse(?) suppose I'll have to take it all apart. Again.... Quote Link to comment Share on other sites More sharing options...
mr vigton Posted March 4, 2014 Author Share Posted March 4, 2014 Update: the discs are shot! Cannot believe I didn't notice first time round, but then that's what comes of having only half your mind on the job in hand.... New discs it is!! Quote Link to comment Share on other sites More sharing options...
Tim_343 Posted March 8, 2014 Share Posted March 8, 2014 Warped disks cause what youve described its almost thr same as driving a car with abs under heavy braking where they forceably push back on the brakes. Quote Link to comment Share on other sites More sharing options...
Toledo Man Posted April 3, 2014 Share Posted April 3, 2014 Warped discs are caused when you keep your foot on the brakes when the car is stationary such as when queuing at traffic lights. With the front brakes applied the discs cool down unevenly and they get warped. The best way to prevent this is to use the handbrake more (wasn't this taught to us when we had drivng lessons?). Strangely enough, I discovered this little pearl of wisdom from the former editor of Triumph World (his name eludes me at the moment) who answered a question from an Acclaim owning reader with the very same brake problem. If you haven't done many miles you should be able to reuse your replacement pads with the new discs but they will need bedding in all over again. Quote Link to comment Share on other sites More sharing options...
mr vigton Posted April 7, 2014 Author Share Posted April 7, 2014 I've changed the discs & pads and overhauled the rears too and mot'd the car (woo hoo!) so it lives to drive another year. Was amazed how bad the discs were: such an idiot not to notice first time... Duh.. Should point out though that getting hold of a pair of front discs was NOT easy!! Rimmer Bros no longer do them & although plenty on eBay they're 'out of stock' when you try to buy. Smaller size rear shoes also nla !! Be warned: if you think your brakes will need overhauling any time soon start looking for parts now is my advice... Quote Link to comment Share on other sites More sharing options...
JohnD Posted April 7, 2014 Share Posted April 7, 2014 Warped discs are a myth - ask Carrol Shelby. he's dead, but his opinions are online.And "Bedding in the pads" is NOT allowing them to conform to the worn profile of the old discs. If the discs are that bad, you do need new ones! The bedding in process allows the pads to heat right through to their working temperature, driving off any residual solvents and other volatile components after manufacture, and without excessive heating anywhere. Lots of 'recipes' on the 'Net for doing so - basicly brake from progressively higher speeds, over about twnety minutes, never stopping and never leaving your foot on the pedal when not braking, until you are braking from the highest speed you expcect to use, to a walking pace, then stopping and leaving the brakes to cool.Keeping your foot on the pedal when stationary and with hot brakes can cause uneven braking, but not by 'warping'. That causes the brake material to become imprinted on the disc surface, changing the friction qualities in that region. Thereafter, instead of being the same friction all the way around the disc, it snatches where the brake material remains. This process causes localised heating and further deposition, making it a self-perpetuating process. Skimming the disc removes the brake materail and so seems to cure the 'warp'. John PS Mr.V - you didn't say what was wrong with you old discs. Please tell? J. Quote Link to comment Share on other sites More sharing options...
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