I recently tried to replace the brake pads on my 88 260e, because of the extream wear on the pads the caliper pistons were extended all the way and when i tried to push it back in the piston hyperextened and came out and i lost some brake fluid. I got th piston back in and nothing seems to be leaking but there is air in there. What do I do, local ripoff mechanic says I need new calipers, when i asked about caliper repair kit he said I would have to heat the piston, freeze the seal to get it on, and it was just easier to get new caliper. Please give me advice I usally can fix anything but hydrolics are new to me. Also money is a consideration if i had it i would have let the mechanic rip me off, please tell me the cheapest way to fix

if the piston went back in without losing any parts like the rubber seal that is around it then you should be able to bleed the brakes and get back in business. reassemble the caliper with the pads, have someone pump the brake pedal til it is hard then hold it firmly. you loosten the brake bleeder valve and let out fluid til the pedal is on the floor. shut the valve off and have them pump it up again. do this til there are no bubbles coming out when you release the bleed valve. then test drive. if the pedal feels normal you are fine. if the pedal will pump up after starting too low, you need to bleed again. keep a close watch on the resorvour to be sure you dont run low on fluid in the process taking care to note that there are two compartments in it that both need to be full. allowing one to get dry will reintroduce air into the line.

good luck. check back if you have any questions. dont drive car if the pedal doesnt feel right.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Minor nitpick: Letting the brake pedal hit the floor is a good way to damage the master cylinder. Over time, crud in the brake fluid can deposit in the MC bore, while the part of the bore that the seals travel is swept clean. Allowing the pedal to exceed normal travel will drag the seals over these deposits and often causes an internal leak. I usually use the toe of my boot under the pedal so as to keep the pedal from hitting the floor. A block of wood would also work.

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1989 300 SEL that mostly works, but needs TLC

about the hitting the floor thing. but apparantely it doesnt cause problems very often. i have been doing it that way for 40 years and never had a problem.

it is prob a good idea to do as he says... i never will be able to remember to do it though.

tom w

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Even if it does not happen instantly, it will likely contribute to the eventual demise of the MC seals. If you're fanatical about changing brake fluid, it may never happen to you. If you've ever looked inside a leaky wheel cylinder, you've seen what can happen inside the master cylinder. In any case, there is no advantage to putting the brake pedal on the floor while bleeding brakes, and it could cause harm.

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1989 300 SEL that mostly works, but needs TLC

what does the brake bleeder valve look like, is it black with threads on the outside? when i turn this nothing happens and i cant get it out

i got the valve cap off and pumped and relases but no air or fluid came out, was running low on fluid so I stopped until i get more , don't want to risk more air

The bleeder valve is a little nipple. It will have a hole in the end of it and a nut at the base... maybe around 10mm. It takes two people to bleed the brake lines.

Also you must hold the brake pedal down untill nipple is tightened again. Procedure is: pump pedal a about 6 times, hold foot pressure on down pedal, have assistant open nipple while pedal is being pressed down, then retighten nipple beffore the pedal is released. Then repeat entire procedure, until solid stream of fluid flow from nipple.

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Earl



1993 190E 2.3
2000 Toyota 4x4 Tundra