|
|
|
#1
|
|||
|
|||
New caliper won't release
I just put two new front calipers/brake lines on. Bled with a power bleeder at 8 psi. Brake pedal is firm, but I think one of the calipers is stuck. Start the car and after braking a couple times, it feels like I'm fighting the brakes. What would cause this?
__________________
1981 300D 205,000 mi. |
#2
|
||||
|
||||
Rubber brake line from the fender to the caliper may be bad. They can swell and cause the caliper to stay applied after braking. Open the bleed screw and if the caliper releases then it is probably the hose.
Dave
__________________
1970 220D, owned 1980-1990 1980 240D, owned 1990-1992 1982 300TD, owned 1992-1993 1986 300SDL, owned 1993-2004 1999 E300, owned 1999-2003 1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD 1988 560SL, 100,000mi, owned since 1995 1965 Mustang Fastback Mileage Unknown(My sons) 1983 240D, 176,000mi (My daughers) owned since 2004 2007 Honda Accord EX-L I4 auto, the new daily driver 1985 300D 264,000mi Son's new daily driver.(sold) 2008 Hyundai Tiberon. Daughters new car |
#3
|
|||
|
|||
the rubber hoses collapse internally, so while it may look OK from the outside, it will pass fluid to the caliper when you step on the brake pedal, but will not return to the m/c. This will also give you a hard brake pedal. Follow the advice above to diagnose bad hose.
|
#4
|
|||
|
|||
You would not be the first to change a sticking or stuck caliper out before checking the flex hose for problems first. Always make a habit to just loosen the flex hose at the caliper before unbolting the caliper if it is suspect.
Applies to american cars as well. Remember nothing is lost as you will have to remove the flex hose connection to change the caliper out anyways. On an old caliper it is just sometimes easier than fighting with a rusty bleeder if you have no heat. Plus you might loose the bleeder screw and still find you had a bad flex hose. You then might have created a double header for yourself. I did it once myself but never again. |
#5
|
||||
|
||||
perhaps your rears are now causing problems... did you bleed them too?
__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread "as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do! My drivers: 1987 190D 2.5Turbo 1987 190D 2.5Turbo 1987 190D 2.5-5SPEED!!! 1987 300TD 1987 300TD 1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere! |
#6
|
|||
|
|||
vstech, I hadn't heard that air in the lines can cause a stuck caliper. I'll try bleeding them again tomorrow maybe.
__________________
1981 300D 205,000 mi. |
#7
|
|||
|
|||
And they sure should be able to take a whole lot more than 8 psi. I do mine at least at 20 psi. You get a lot more than that when you apply the brakes.
__________________
Len '59 220S Cabriolet-SOLD and living happily in Malta '83 240D 351,500 miles original owner-SOLD '88 560SL 41,000 miles - totaled and parted out https://sites.google.com/site/mercedesstuff/home '99 E300 turbo 227,500 miles '03 SLK320 40,000 miles - gave to my daughter '14 Smart electric coupe 28,500 miles '14 Smart electric cabriolet 28,500 miles '15 Smart electric coupe 28,000 miles |
#8
|
||||
|
||||
How were the calipers when you changed pads?? did the pistons retract easily and smoothly?? if it is a bad caliper, I would suspect that there were tell tale signs when you did the brakes.
did you remove the caliper, or just do pads, prying the cylinder back in??
__________________
1984 123.193 372,xxx miles, room for Seven. 1999 Dodge Durango Cummins 4BTAA 47RE 5k lb 4x4 getting 25+mpgs, room for Seven. |
#9
|
|||
|
|||
Were the calipers new or were they overhauled? Did you replace the front brake lines and the brake hoses?
|
#10
|
|||
|
|||
Even though you have just put new parts on test like you where just starting to check out a brake malfunction. If you can locate the side with the suspect caliper try pushing the pads back. If no go loosen the bleeder as its new and moves easy. See if it caliper will retract then. If it were both sides the master cylinder would be suspect. Only one side rules that out. Also be careful reaching a decision. As even a new hose for example could be faulty. Not likely but possible.
|
#11
|
|||
|
|||
The sympton appears to be: the fluid is being trapped in the caliper. the caliper is not releasing. bleed it. try the brakes again. If you get the same hard pedal and the caliper won't release, change the hose. I'd suggest doing both sides. new calipers=new hoses!
No more problems up front. The master won't cause this kind of problem that I can remember. |
#12
|
||||
|
||||
seems the lines are new, everyone....
__________________
1984 123.193 372,xxx miles, room for Seven. 1999 Dodge Durango Cummins 4BTAA 47RE 5k lb 4x4 getting 25+mpgs, room for Seven. |
#13
|
|||
|
|||
There are brake lines and there are brake hoses. It's not clear to me what is new and what isn't.
|
#14
|
|||
|
|||
If your hoses are new, I'm going to suggest a tipped piston in your caliper. This will require removal of the pads and a visual inspection. Usually best to take caliper off rotor to view it.
|
Bookmarks |
Thread Tools | |
Display Modes | |
|
|