R129 binding front brakes

Page may contain affiliate links. Please see terms for details.

nap27

New Member
Joined
Apr 10, 2013
Messages
29
Car
W211 E320 CDI, R129 320SL
Hi
Just had new rear springs, shocks and a suspension repair kit fitted to my R129 (a 1998 320 SL with 98K on it) the rear was sagging and also several bushes had disintegrated, now it is sitting slightly higher at the rear is firm with great ride feeling very tight, better rear traction, no wondering on the road, no squeaks or thumps any more. Brakes have always been fantastic no issues.

Whilst this work was being done the rear brake pipes were noticed to have perished so these were also replaced and the brake fluid changed (which i normally have done very two years anyway and was due). Pads were also taken out and cleaned off before refitting.

After collecting driving home (a 5 minute drive) the brake pedal was rock hard, not normal for an R129 and stopping at home the BAS/ASR light came on. I assumed as the boot had been open for at least 10 hours and they had started and moved the car multiple times this was a low voltage issue.
Turned car off and on again and the light went off

Going for a longer test drive after 10 minutes or so felt lots of resistance needed 1/2 throttle just to do 30 and then i smelt brakes.
The front wheels were black with brake dust and smelling very hot
Left it cool down at the side of the road and went to return to garage, driving back pedal went to its normal feel (slightly soggy, long travel but progressive with some feel and fantastic stopping power)
Back to garage all wheels are cool check it over and nothing abnormal can be found, whilst idling the BAS/ASR light came on again - turning car on and off light went off.

Charged battery overnight (was 70% charged when i got home) and went for a drive today, 10 minutes into it front brakes are binding on and pedal is rock hard. Need almost 50% throttle to do 30 mph. After letting the car cool down at the side of the road driving back to garage it seems to return to normal no resistance and normal SL brake pedal feel

Anyone got ideas as its back with mechanic but he is scratching his head....
 
Mechanic scratching his head - find a better one quickly considering you had fantastic brakes before you took the car to him.:crazy:
 
i'm thinking that as they bleed the brakes the old fashioned way either we have
1) air in it - which might explain why its ok to start with and then after some minutes pedal goes hard brakes on front come on, after allowing to cool its ok - perhaps because the brake fluid has boiled ?
2) they have by depressing the brake pedal to the floor blown the master cylinder seals
3) front flexible pipes are collapsing and need replacing?

Hoping its 1....
 
Item 3) causes this.
The inner wall of the hose collapses when the brake is released trapping fluid in the caliper and holding the brake on.
Caused, IMO, by clamping the hose (to stop fluid emanating) when calipers are removed.
 
Thanks for that, that would be ok as i would expect to have to change them if the rears have perished and on a 98 car that's not to bad for life span, will have a look at them. Certainly more attractive than changing the master cylinder ...
 

Users who are viewing this thread

Back
Top Bottom