soft brake pedal

[max411]

Hi guys, I have a sprinter cdi313, the brakes are just crap, with soft pedal, pads are all ok, if i pump the pedal it goes hard ,any ideas,?

 

[Rockron]

Usually air in the brake system (brake lines and/or wheel cylinders) bleeding the brake system is the remedy.
Sometimes if the brake fluid (hygroscopic) is old, it absorbs water from the atmosphere, when the brakes get hot this heat can get transferred to the water in system which boils, steam is compressible which means sponginess and more movement required at the brake pedal. Again the remedy is bleeding the bleeding brake system....thoroughly.

 

[mioba]

Beyong bleeding, when was the fluid last changed - every two years. Simple enough job and its a good time to change the bleed nipples before they break and eave you in a world of pain.
Spray new nipples with waxoly and make sure to use a cap on them so they dont get water in a and rust (will then last a long long time).

 

[max411]

will get them done, cheers

 

[max411]

cannot say when fluid was changed, as i have had this van less than a year, but will get that done also,

 

[Steve@Avantgarde]

Do a few master cylinders on Sprinters.

 

[Rockron]

At one extreme is an 'annual' brake fluid change,as stipulated in my MB commercial vehicle maintenance schedule, at the opposite extreme is 5 years attributable IIRC to a Lada schedule!
Perhaps MB are OTT, after all they quote a ' hydraulic' system when almost without exception their vehicles run an 'oildraulic' system, They're not perfect.

If the fluid change does nothing to alleviate the sponginess then next to investigate is air bypassing the seals. Quote by Steve@Avantgarde suggests master cylinder being perhaps first point of call. In my experience (not a pro mechanic) if air is getting in, then there's usually external signs of brake fluid leakage, and the fluid reservoir needing topping up.

.

 

[ajlsl600]

On fliud change. Not saying it best policy. But I have never in more 40 Yr done a scheduled fluid change. I have done that at any m,cyl change and and wheel cyl change and a partial at any caliper reseal

 

[Rockron]

On fliud change. Not saying it best policy. But I have never in more 40 Yr done a scheduled fluid change. I have done that at any m,cyl change and and wheel cyl change and a partial at any caliper reseal

Mind you I suppose that if you regularly replaced or had to repair brake system components, then maybe you were renewing the fluid every 6 or so months anyway

 

[ajlsl600]

Not at all. For example I never changed a pipe flex or origional o w208 or cyl or m cyl. But I changed flexes and all origional metal on th w168

 

[max411]

Hi guys, got van back, was told needed back brakes replaced, fluid changed, pedal a bit harder but not happy with pulling up distance, i also have Kangoo van you just Touch the brake pedal & you're stopping, just not happy with the merc, in case of a hard stop,

 

[ajlsl600]

U cud go to mot centre and test brakes on r Road. Otherwise change ur rear linings check ur front pads n try again
If u relax ur grip a bit and brake does the vehicle pull up in straight line? If u go test. Find quite road and use middle sometimes cars pull into the camber a bit.

 

[max411]

van pulling up straight line, psv up jan 18, cannot feel brakes biting, just a slow stop, hairy when traffic lights turn you