200ci66

I'm starting to have problems with my brakes. I was going down the road today, when all of a sudden, the slight tap of the brake pedal pushed it to the floor as if all the pressure was gone, and braking was almost nonexistent (but still enough to notice a drop in speed). After about 10 seconds I pushed the pedal again, and the pressure came back. This happened again and again as I putted home slowly. Stock drum brakes, no power.

So I have two questions: Do I definitely have a leak somewhere, or could I just be mistaking it for typical pedal fade? (We drove the car for about four-five hours today with constant braking, more than we've ever driven the car before)

Also, do you guys have any advice on getting the lid to the master cylinder off? Ours just won't budge.

rtintwo

Sounds to more like a master cylinder going bad sense you could pump it up and have brakes. If it was a leak the pedal would be very spongy all the time. Brake fade ussually wont go away until the brakes are cooled down.

If the lid wont unscrew use a big pair of channel locks and a rag to unscrew it. If fluid levels good, take a look at your lines, hoses and inside the drums for issues. If thats all good i would replace the master cylinder and this would be a good time to do a dual bowl conversion.

guitarman376

It is possible that the built-in residual pressure valve (inside the master cylinder, 10 psi for drums) failed causing the first application of the brakes to simply stretch the drum shoe return springs and the second push to actually apply some braking.

200ci66

I'll get the master cylinder cap off there and do some investigating next. I don't think it's a leak in a line because there are absolutely no leak puddles on the ground or anything like that when I pump the brakes, but then I guess checking the fluid level is the first thing to do before assuming stuff.

Another question, I've been reading that this could be from brake fluid boiling. I haven't changed the brake fluid, and god only knows when any of the other owners changed it. Old brake fluid boils easier correct?

And yeah, I was planning on converting to a Power Brake Booster with a dual master cylinder this winter. It looks like that project is going to be pushed forward a little bit.

Oxnard Montalvo

It's a classic symptom of a bad master cylinder. See if rapidly pumping the brakes gives you a better pedal (better, not perfect.) If it does, the mc cups are worn and the brake fluid is leaking by. Changing to a dual mc asap is a good idea anyway.

200ci66

Yes, this is exactly what happened. Almost exactly how you said it. It's almost like the pedal goes dead, but if you pump it to the floor 2 or 3 times it goes back to normal for about 30 seconds. Then randomly goes dead again.

And I got the master cylinder open today, and it looked... used to say the least. I'm now saving up for http://cgi.ebay.com/ebaymotors/Power...#ht_1438wt_732

Will replacing my old master cylinder with that eliminate the problem (assuming that it's the master cylinder and not a leak?)

67t5ponycoupe

You can get a replacement master cylinder at Autozone or Checker today and have the thing up and running. That ebay deal looks like a big waste of money.

Oxnard Montalvo

67t5 is right, unless you live for chrome and gotta have power brakes you can get away a lot cheaper than that kit.

CJ Pony article and parts.

All the parts listed are available at many parts stores, and if you use a Maverick MC the pedal rod that comes with it is the same size as your old one.

200ci66

Well I was originally going to upgrade to power brakes anyway. That was my main motivation behind buying the kit before I had this problem. The fact that it's chrome is actually a turn off for me, but it's cheaper than the oem kit that you find in any of the catalogs.

67t5ponycoupe

Chrome goodies always sound like a good idea until you are the one that has to keep the shinny stuff clean. I would recommend just doing the dual bowl master upgrade which includes doing some plumbing work and seeing if that fixes your problem. If not at least you will have done a nice upgrade that was needed anyway.