R129 brake bleed issue.

[Old Merc]

I`ve just given my 1997 SL320 its annual service including a good brake bleed.Nothing wrong with the brakes,pads and discs are good,just gave it about 20 pumps of the pedal on each corner,topping up regularly.I`m old fashioned and use a rubber pipe from the nipple to a bottle,done this for years without a problem.
As soon as I went for a drive I noticed the brake pedal was right at the top,just touch it and you had brakes.After about 20 mile run the brakes were binding on all four wheels,left it to cool and they were free.
I gave them another bleed but this time I had my wife on the pedal,engine running,open nipple pedal down,close nipple pedal up,about six times each corner.
I now have more travel in the pedal,I gave it a good hard run and no binding,so sorted? but why did this happen?
I`ve had this car for about ten years and have never been happy with the feel of the pedal.
What thoughts do you R129 experts have?

[r129sl]

I cannot offer any insight but I do share your misgivings about brake feel in the 129. My car has great brakes but the pedal is very long and soft in travel. It has never felt sensitive or forceful at the top of the pedal.

[Old Merc]

Thanks R129SL, looks as if we all have this "soft pedal".

I wonder why I got that firm pedal? The brakes were fantastic,just touch the pedal and it would stop dead.BUT! they were too good,no pedal travel.
Good job I road tested it,we are off to Devon tomorrow and would have ground to a halt on the M5 with binding brakes.

I have a feeling a new master cylinder is the next job.

[PositronicRay]

Mines long and soft (oh er misses)

I pressure bleed, easier and less risk of damaging seals

Enjoy Devon,

[r129sl]

A new master cylinder made no difference to my car's brake feel. I've also just had the front callipers rebuilt; the rears are new; and the discs and pads are new all round.

I think they just have a long and soft pedal. It takes some getting used to in these days of instant-forceful-bite brakes, but actually it allows for smoother and more measured application of the brakes. The strength is there however. On one of my "private" test strips a three-quarter mile straight is followed by a sharp left. I love hauling it down from 145 to 50 on the cusp of ABS intervention. I never feel it is wanting for stopping power and one of these days I'll get to 150! And trigger the BAS by a sharp step on the pedal and you find yourself picking teeth out of the steering wheel.

[chris333]

Yup, mine's long and soft too.

As r129sl says, they are actually more than powerful, just designed in a more relaxed age so Lady Di could pull up softly outside San Lorenzo.