datzenmike Posted March 17, 2017 Report Share Posted March 17, 2017 Usually trapped pressure in the front is because the pushrod is not fully returned to release it. Can't have one side on and the other off so could be the caliper or, here's an odd one.... The flex line is coming apart internally and blocks the return flow of fluid. In other words it becomes a one way valve. Loosen the flex line fitting at the caliper, if this releases the pressure then this is the problem. I've had a caliper stick before and the rotor got smoking hot and smelled like a burning clutch. Used a tire iron to pry the pad and caliper piston back into the bore. Pumped the brakes to bring the piston back out and.... it was fine. Quote Link to comment
TheBirdistheWord Posted March 19, 2017 Author Report Share Posted March 19, 2017 Usually trapped pressure in the front is because the pushrod is not fully returned to release it. Can't have one side on and the other off so could be the caliper or, here's an odd one.... The flex line is coming apart internally and blocks the return flow of fluid. In other words it becomes a one way valve. Loosen the flex line fitting at the caliper, if this releases the pressure then this is the problem. I've had a caliper stick before and the rotor got smoking hot and smelled like a burning clutch. Used a tire iron to pry the pad and caliper piston back into the bore. Pumped the brakes to bring the piston back out and.... it was fine. Disconecting the hose didnt yield any results so im assuming the piston is got pushed out too far while I was repeatedly building and holding the brake pressure over the last few weeks. How important is the circular spacer/spring that goes into the piston cup? The caliper fits without it, and if the piston is blown out past its seal it hasnt started leaking yet. However if it IS actually past its seal, leaving the spacer/spring out without correcting it will just put me right back where im at now. Is it necessary to remove the brake line to push the caliper piston back into the bore? I cant really visualize how you pulled it off with a pry bar, my C-clamp isnt doing much, but I think its bent and locking up before its useful. gonna buy another and try again.... Quote Link to comment
TheBirdistheWord Posted March 22, 2017 Author Report Share Posted March 22, 2017 I have bent or broken every tool I have tried to compress this piston. Does anyone know of a trick? seems to be bottomed out but it still wont fit over the pads without removing a spacer on the pad or the caliper. Quote Link to comment
yello620 Posted March 22, 2017 Report Share Posted March 22, 2017 You are fighting a losing battle messing with that caliper piston. Just remove the caliper and use it as a core at the parts store to get a replacement. Even if you did get the piston to move back in, it will just stick again in the future and cause more problems later. I have no idea what you are talking about with a "spacer" at the piston. Never seen a "spacer before except in some custom "race" stuff. Are you just talking about normal pad shims? Quote Link to comment
TheBirdistheWord Posted March 24, 2017 Author Report Share Posted March 24, 2017 You are fighting a losing battle messing with that caliper piston. Just remove the caliper and use it as a core at the parts store to get a replacement. Even if you did get the piston to move back in, it will just stick again in the future and cause more problems later. I have no idea what you are talking about with a "spacer" at the piston. Never seen a "spacer before except in some custom "race" stuff. Are you just talking about normal pad shims? its a fresh caliper from rock auto! but im thinking you might be right. the pad shims are the pad shims, maybe spacer is the incorrect term, its a very thin circular shim the exact circumference of the caliper piston doubled up. I have got enough play to turn the rotor with the wheel installed with light/moderate force. if it locks up after this ill replace it again..... ::sigh:: Quote Link to comment
datzenmike Posted March 24, 2017 Report Share Posted March 24, 2017 If between the piston and the back of the pads it's the anti rattle shim. It will work without them. When the pad wears down slip them in. Recently someone had new replacement brake shoes that the drum wouldn't fit over.... turned out the manufacturer used thicker lining material. Also make sure the caliper is 'floating' and free to slide side to side. Quote Link to comment
TheBirdistheWord Posted March 24, 2017 Author Report Share Posted March 24, 2017 If between the piston and the back of the pads it's the anti rattle shim. It will work without them. When the pad wears down slip them in. Recently someone had new replacement brake shoes that the drum wouldn't fit over.... turned out the manufacturer used thicker lining material. Also make sure the caliper is 'floating' and free to slide side to side. I was thinking this could be a pad tolerance thing, paired with the remen calipers allowed for some play initially and once it was fully pressurized it tightened up. Which would mean the piston was never popped out. Which in turn would explain why I keep breaking tools lol Quote Link to comment
jeffball610 Posted April 18, 2017 Report Share Posted April 18, 2017 I'm having trouble with my system too. I don't think your "fix" will help me, but I'll take another look. I've bled the system from the MC all the way around several times, and I still have a ton of travel before I have any brake feel. Once it does give resistance, it's kind of spongy. I might get a new MC, but I'm not sure that will solve anything. The only reason I would think my MC was bad is that it sat in the car new and dry for about 5 years before I built the brake system. I'll take another look at my pedal adjustment as well, but it's threaded out as far as it will go. I wouldn't think a longer rod would be needed, but maybe it does. If so, wouldn't that move the pedal further from the floor? Quote Link to comment
datzenmike Posted April 18, 2017 Report Share Posted April 18, 2017 Did you bleed the master first? Quote Link to comment
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