Brake System Troubles

[Brenton]

OK. This one is tough to describe. My brake pressure is fine. In fact it's solid. However, I do not get good stopping power. The pedal seems to almost bind up just when the pressure is starting to get really good. So as a result, I have to STAND on my power brakes in order to stop properly. I thought my Power Brake booster was binding - so I replaced it. It got a little better. I thought mebbe I had a plugged line (It will go to the floor if I release one the bleeder valves on the wheel cylinder). I had a lot of crud in the rear line - it's all gone - it got a little better.
I'm starting to think Master Cylinder or proportioning valve. So here's the situation. I am rebuilding a '68 Gladiator, and converted to power brakes using a system from a '71 Wagoneer. Brakes worked great on Wago, old system on truck worked. After swapping out - no worky. Can anybody tell me if the Master Cylinder and/or the proportioning valves are that dissimilar on these two vehicles? I don't want to throw $500 worth of parts at the brake system only to find out it was only one part of the equation that was wrong! I eventually intend to get it all rebuilt, but for right now, I wanna get it working acceptably so that I can DRIVE the stinkin' thing. (The brakes and drums themselves are in good enough shape). In that same vein, if I need a proportioning valve, does anyone out there have the correct valve for a 1968 Gladiator with power brakes (or know where to get one - JWJEEP says no have). I suspect anything from '63 - '69 would work fine as a substitute. If it's my master cylinder - I'll kneel down, and kiss each dollar I spend at NAPA for a replacement. Any help would be GREATLY appreciated. I've invested over $6K, and 2 summers, to have the money run low, and be stopped from roadin' by the stinkin' brake system - that shouldn't have been in question!!

[joe]

A vacuum leak or a sticking/inop check valve will cause a hard pedal.
So far as the masters being the same I'm not sure what side of the early/later line a 68 falls on but the 69's used the same Bendix system as the 71's but say 66 used a Midland system with the manual tranny and a Bendix system with the AT's. Those should be obviously differnt though. The earlier Bendix had a throw on the push rod of 1.245"-1.250" and the later 0.980"-0.995"
Again I don't know the change year was, if it was 67, 68 or 69?
If you can't find a vac leak I'd get a new vac check valve and see what happens. It's a cheap-n-easy thing to start with.

[Brenton]

Thanks a Ton. As far as the switchover goes, My '68 is identical to the '69, so if they're the same system as the '71, then I'm happy. I'll check it out tonight. What about the proportioning valve. I'm pretty sure the Master Cylinder is correct from the description you have given. Could it be different enough to cause funky brake issues?

Brent

[joe]

If you're sure your 68 master is the same as a 69 then it'll be the same as a 71. Also the prop valves have the same p/n's so you should be good to go so far as compatabilty.

[Brenton]

Excellent, sorry to hound this, but the Prop valve is the same P# for '71 Wago as '68 Gladiator, or '68 and '69 Gladiator are the same with the '69 being the same as the '71. Thanks for helping put my mind at ease on this. If I can eliminate the prop and MC as being different parts, then I KNOW to look elsewhere, and mebbe go ahead and rebuild the remaining system sooner than anticipated.. It's starting to sound more and more like I got a leaky vacuum system, or a defective replacement on my newly replaced brake booster...

Brent

[joe]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Brenton:
It's starting to sound more and more like I got a leaky vacuum system, or a defective replacement on my newly replaced brake booster...

Brent<HR></BLOCKQUOTE>
That would be my guess Brent. Generally a hard pedal on a PB system is vac related prob not allowing the booster to work properly. Could be a bad booster, vac check valve, kinked/leaking vac hose etc.

[Brenton]

Thanks, I'll check it out tonight, and post my findings over the weekend or Monday. Thanks for your help Joe.

[Brenton]

I got it. There was a vacuum attachment that has 2 attachments, one for the brake booster, and the other was sucking air. I plugged it, and now it stops like a truck with four drum brakes that need replacing, turning, and rebuilding.

Brent

[joe]

Glad ya got it figured out and it was a cheap-n-easy fix.
Yeah, vacuum leaks will bite ya