Ilovemountains

I just took my truck out to grab a bite to eat at lunch and had to really jump on the brakes, to my surprise the pedal mashed all the way to the carpet and I didn't have a single wheel lock, it didn't even feel like they were close to locking, that was at about 15 mph!! I pulled back into the parking garage at work and the master looks fine, still full, no visible leaks on the wheel cylinders or calipers. The rear brakes are almost new and the fronts are about 3 years old with over half pad left. I bled the entire system out last year and it has not lost a drop of fluid since. Could my master be failing??? Could it fail without leaking?? Im going to drive very slowly home because I don't know if its going to just give out all together. Before I jump the gun and buy and replace the master do you guys think thats what it could be?? Its like its not holding pressure but not leaking either... Any input would be great! ~Matt

crafthorse

I would have to say I woulod think it is the master, I had a 91 chevy do the same thing, and it was the master.

Lumpy

Could need a rebuild. I don't think those kits are but a couple bucks...

http://www.google.com/products?q=mas...kup&hl=en&aq=f

Ilovemountains

Ive never had any luck with rebuilding clutch masters, they always start to leak for some reason. Do you think that its worth rebuilding with 185,000 miles on it or would it be better to just buy one from Car Quest and go for an extra $40???

Lumpy

I rebuilt one on a 67 Toronado and on a 80 Bronco and never had an issue. Did the clutch cylinder on a 80 280ZX as well. They all held up as far as I know, then again back then I didn't keep cars too long. Personally if it were me, I'd rebuild and use the extra $40 for a good case of beer while you rebuild it.

lofreqjeff

I have a brand new Trail Gear Master Cylinder that I got from a memeber on here but it ended up not working on my truck:

http://trail-gear.com/brake.html

Let me know if you're interested

Ilovemountains

I may be interested! What would you want for it shipped to 664 Carter Ave. Harpers Ferry, WV 25425? I wonder if they are rebuildable too. I may just rebuild mine, I like the $40 for the beer idea

tc

Pull the rear drums and see if you have an axle seal leak before wasting money on a master cylinder.

Ilovemountains

I just replaced my drivers side rear wheel bearing and seal and the pass seals when I replaced the rear end a little over a month ago, everything is 100% dry, I would hope that at 15mph I could lock a front wheel even if the rears were not working!! Im just glad I didnt realize this was happening with my trailer on the truck with a load or coming back from Franklin WV on 33!! YIKES!

tc

While the braking is primarily handled by the fronts, the feel and the travel are determined by the rear brakes ... after you put everything back together, did you adjust them?

http://personal.utulsa.edu/~nathan-b...akesystem.html

(NOTE: I'm not ruling out a master cylinder or brake booster - just a lot more likely things to check first. Usually, the MC and booster go slowly and you see it getting worse and worse)

DJ99

Did you use the pump and hold method of bleeding when you did it last? That can lead to quicker MC failure when the piston is pushed past its normal travel and the seals get scratched up.

Coincidentally, the MC in my Acura went out yesterday. I was stopping at a light and the pedal went to the floor, but still stopped the car. Not a good feeling at all! I got a rebuilt at NAPA for under $70 and it wasn't hard to replace.

I highly recommend Russell speed bleeders or a mighty-vac or both for easy on the MC brake bleeding. Just don't pump the pedal too far on your old MC with speed bleeders.

Ilovemountains

I used a large vacuum bleeder when I bled the entire system with new fluid, though when I did the rear axles and rear end I used the old pump method, I have noticed the brakes getting spongy so there is a very very good chance the master has finally died! I did adjust the rears just to the point that they were ever so slightly touching the drums and backed them off one click. Im going to investigate it this evening or this weekend, my thoughts are even if an axle seal is leaking and the rear brakes are covered in oil they would still hold pressure in the system and the pedal wouldn't go all the way down, they just wouldn't create friction!

wyoming9

iTrader: (1)

I looked into doing this the rebuild kit is almost the price of a rebuilt Master Cylinder at Napa. that was a no brainer

WatsonToyota

i had a "fun" time chasing a brake problem not too long ago and discovered it was a faulty load sensing proportion valve....

12crawl

You can still use your parking brake in a pinch.too late now,hope you made it home safely.