Diagnos - Master cylinder on Chevy van

[czechsonofagun]

On every complex system, the first part to go bad is the safety feature. It could qualify for another Murphy's law IMHO.

 

[RobS]

Hello folks, I drove the van with the fuse pulled for the ABS. Other than the ABS fault light on the dash, I did'nt notice the pedal feeling any differently. I've also tried some panic stops from about 40mph with the ABS enabled and without. The brakes are strong and effective. I'm beginning to think that the pedal feel may be normal for this vehicle. I've been driving Buicks for the last two years and maybe they just have a softer feel with less pedal effort.

To be safe, I'll have my local (trusted) mechanic give it a test drive when I have him inspect the front end components this week.

Thanks for your help.

If it's got a Hydro-Boost instead of vacuum (which it could), it does indeed have slightly different pedal feel. Drive another Hydro-boost vehicle (about any diesel pickup truck) and compare to that. Definitely doesn't sound like an ABS or master cylinder problem.

 

[BobRip]

On every complex system, the first part to go bad is the safety feature. It could qualify for another Murphy's law IMHO.

The backup system will fail and take out the primary system.

 

[dbdartman]

I just did a hydra-boost swap into my bro's 69 Coronet 500 wagon last spring. We used a Chevy/GMC 1500 unit. He researched this for almost a year before choosing the truck piece (over the van & Caddy parts among others). One thing I remember him mentioning was that those small van hydra-boost units have a reputation for being problematic.

Having driven his wagon for the first time a couple weeks ago, I have 2 observations:

First, I don't care if this thing does weigh over 4500 lbs with both of us in it, with 550HP & 590 lb/ft on tap it's FAST!

Second, with the hydra-boost & 11.75"/11" disc/drum brakes brake effort is very light & linear.