Losing brake pressure at stops

mikracer · 10-08-2015, 04:26 PM

My van has never had really good brake pressure or feel since I bought it last year. It's always been a little mushy and soft. Now at stop lights, the pedal will lose braking force and the van will creep forward unless I add more pressure to the pedal.

My question is, if there aren't any fluid leaks, would this just be air in the lines? Not sure when the last fluid flush was, but I've had it for about a year and a half and I haven't flushed them yet.

rallypanam · 10-08-2015, 04:48 PM

Quote:

Originally Posted by mikracer

My van has never had really good brake pressure or feel since I bought it last year. It's always been a little mushy and soft. Now at stop lights, the pedal will lose braking force and the van will creep forward unless I add more pressure to the pedal.

My question is, if there aren't any fluid leaks, would this just be air in the lines? Not sure when the last fluid flush was, but I've had it for about a year and a half and I haven't flushed them yet.

I'd guess there is a fluid leak.. Potentially in master cylinder if nothing looks leaky on the calipers. But I'm no mechanic.

BajaSportsmobile · 10-08-2015, 04:51 PM

Check the fluid level to see if it is low, suggesting a leak, and look at each corner for leaks. Most likely you will not find an external leak, in which case the Master Cylinder is bad.

mikracer · 10-08-2015, 04:56 PM

Thanks guys. Is there any other way to confirm that the master cylinder is leaking internally?

rallypanam · 10-08-2015, 05:00 PM

Quote:

Originally Posted by mikracer

Thanks guys. Is there any other way to confirm that the master cylinder is leaking internally?

I think if you have this symptom, and are losing fluid as per Ramsey, and you see no fluid on lines or calipers, then it's very likely the master cylinder. It's a cheap fix, you can can get a new reman for less than $100.

mikracer · 10-08-2015, 05:02 PM

Got it, thanks. I'll check fluid level when I get off work.

BajaSportsmobile · 10-08-2015, 05:02 PM

You could run a pressure test...

Once you have confirmed no external leaks, bleed the brakes to confirm no air in the system.

If you hold light steady pressure on the peddle and it continues to creep to the floor it is the M/C bypassing internally. Not uncommon on these vans. M/C's are not expensive and a DIY project.

twogone · 10-08-2015, 05:17 PM

Vacuum pump on my 95 was the culprit... but you may not have a vacuum pump on yours

BajaSportsmobile · 10-08-2015, 05:20 PM

His is a V10, not a diesel - no vacuum pump. They can cause similar problems as can the ABS module.

twogone · 10-08-2015, 05:23 PM

gotcha