Going to do battle with some of that super smart brake fluid today. Driver side caliper started sticking, so its coming off. While I’m at it, the master cylinder needs to come off so I can get the pushrod set correctly. Right now, a couple of washers between the master and its mounting surface are providing clearance. Hoping the brake fluid doesn’t outsmart me. Sent from my iPad using The H.A.M.B. mobile app
My better half is a world class expert at “pump and hold”. I’m a lucky man. Sent from my iPhone using H.A.M.B.
I haven’t t yet been outsmarted by the brake fluid. It’s still safely stored in its bottle, where it’s going to stay for a while yet. Swapped the caliper, no problem there. Couple slider bolts, one banjo bolt, and it’s off. Reverse and the new one is on. Then I tackled the master cylinder. I replaced the master a couple years ago, and it didn’t go well. Couldn’t get the system to bleed. Finally got them bled and working, but had them locking up. Was pretty sure it was pin to plunger clearance, so I added a couple washers between the booster and master, which worked, but bugged me as being wrong. So, I pulled the master and started measuring. First thing I found was this: adjustable pushrod, with the end cut off: That was the first clue that this wasn’t going to go well. The shortened pushrod doesn’t actually bottom in the booster. The flats of the nut end are just slightly too big to fit in the hole. So, yeah, it’s just riding on 1/64” of steel. That turns out to be ok. I made a depth gauge and started measuring. I could not come up with a pushrod length that made any sense. The master is from a local muscle car parts shop, and works with either manual (long pin) or power (short pin plus a plug to fill the hole in the plunger). But either setup was too long. I took the butchered adjustable rod and ground the flats off so it would fit in the hole. But even with the pushrod removed, I couldn’t mount the master to the booster without forcing it down on the studs. Pushing the brake pedal showed something interesting: The booster doesn’t push out the pushrod. It has a plunger that extends. And that plunger is what’s actually pushing on the master. The pushrod isn’t doing anything other than maybe keeping the plunger from the master centered on the master. That’s not going to work. After looking at a bunch of pictures, I think I’ve identified the booster as 1987 Chevy, but it takes some weird looking master. I pulled the booster, and will have to go get one that will actually work. That’ll probably mean running new lines too. Eventually I’ll get to the point of refilling and bleeding the system. But not tonight. Today’s lesson is that mismatched parts don’t work well. Sent from my iPad using The H.A.M.B. mobile app
I work alone. Wife not the least bit interested in pump-and-hold. A check valve bleeding kit is my method of choice. I go high tech, though, using my phone to provide a remote view of the caliper to my tablet on the dash, so I can see what it’s doing. Sent from my iPad using The H.A.M.B. mobile app
Brake bleeding with my wife: OK honey, pump... hold...nothing, are you pushing? No, you said hold it so I quit. Argh, OK push down all the way. I can't, the seat's too far back. Shist, hang on.. OK, try it now. Your steering wheel is all greasy. Get out!
You might need to check the rubber brake line, as they age they can and will collapse when hard braking, I chased my tail for a couple of months, I replaced the caliper and the brakes were still pulling. HRP
The hoses are new (2017). Caliper was hard to retract, even with the bleeder open so no pressure on it. Sent from my iPad using The H.A.M.B. mobile app
While cussing and cursing MSD as I have the past week, I also completely rebuilt my front brakes. Two new caliper pistons, (two of the four were okay, four new pads, bought and installed new inner and outer wheel bearings, & seals. Bought and installed new transfer pipes also and had new lines made up that were just barely long enough, adding more length of course. Have that all back together, looking good and so I am also going to get with Mr. DOT 3, right after my two daughters come for "our" (fathers) day. Mr. Mighty Vac, made his appearance last night and is awaiting his opportunity to once again do his magnificent job. And if you have followed my MSD rant of last week, (if you did, my sincerest of apologies), the new wires are complete on the car and next in that saga is wiring the new 1 million dollar distributor which is no big deal. All this is as the result of searching out and fixing the higher RPM miss that I pledged to do earlier this year before Satan decided to bless humanity with his favorite devilish pleasures.
I’ve tried the vacuum bleed several times. A friend of mine swears by it. I’ve never gotten it to work satisfactorily. Sent from my iPad using The H.A.M.B. mobile app
The trick is to wrap all your bleeder threads with teflon tape. Without the tape, many will just suck air around the threads. Makes all the difference in the world....
The Jalopy Journal
