buickbrothers

Never mind, I got the piston to pull out. I soaked the stop ring and adapter ring gaps in PB blaster for a couple of hours. First pull the piston popped out. I'll tell you, without PB Blaster, I'd think you would have a lot more trouble taking apart these old cars and their parts. One last question. I have all the O Ring sizes and seals from Willies (old tanks) listing from a while back, but I'm having some problems finding who to order them from. The two consolidated bearing company seals are hard to find although I can find the same size seals from other manufactures' like RS. The three National seals I can find (now Timken). But for all the O Rings - is there a single recommended source that has all the sizes that I can do one order from? Thanks.

I've disassembled the steering gear box. I'm down to just the power piston. One question, how do I remove the piston from the cylinder? Book says to pull back on the rack sharply to hammer the piston against the adapter to break the grip of the rubber seals between the adapter and cylinder. I did this several times and not getting it to come out or show signs of movement on the adapter. I don't want to force or damage anything so is there a technique to use? A puller? Since this is a piston with rings is it possible there is a lip now on the inner cylinder wall that could prevent removal? I wouldn't think so since it's not like the engine cylinders and high-speed piston movement but thought I would ask. Thanks.

Thanks Ben!

I've pulled off everything so I can now remove the power steering gear box and shaft. Very painful to be going in reverse but this is the last mechanical activity to complete before starting to put all the interior back together and it's the only thing remaining that I haven't rebuilt on this car! So, this may be a dumb question but how do I remove the ball end of the pitman shaft arm connected to the intermediate rod? Do I remove the cotter pin, plug and spring bumper on the end of the rod, and it will just pop out? Nothing in the book of web searches on this. I know I use the puller to get it off the steering gear box. I've got Mudbones video's on rebuilding the gear box and Willie's seal information. Thanks.

Final update on this post. Willie (aka Old-Tank) nailed it. Wow, I'm amazed that adding a vent tube to the boot solved the problem! I cut a half inch piece of small vacuum line tubing, punched a hole in the boot at a baffle and shoved it in. Fired the car up and I have a brake pedal that returns with no issue. Moved the car back and forth in the driveway to test and all is good. I'll take it out for a longer test shortly. The book has nothing about this boot as a potential problem. All of us fixing up these old cars would just assume it's one of several other possible problems. Just goes to show the value of all you senior members in the forum and your knowledge. I was envisioning having to rip the booster back and tearing back into it and destroying all the work, gaskets, paint, etc., to check brand new primary and secondary cups. Thanks so much Willie for this tip! I'll go back now and put some rtv on the base of the vent to bond it in place - don't want this falling out. My last big mechanical item is the steering box tear out and rebuild since it's leaking. Wouldn't it be nice if I could just put a can of power steering sealer in it - lol - is that an option Willie? I'm half kidding since I'm pretty sure the O-rings around the shaft are the problem. Leaking out of the collar at the base. Just dreading this last activity, but I've rebuilt every part on this car so why wouldn't this last item not need it as well. Have a blessed day all and thank you as always!

How would I test if this check valve is working correctly? I cleaned it several weeks ago when I was working on the brakes. I know air flows through, and it's not clogged. It definitely plays a role in the brake "releasing stage" and the small spring is supposed to press against the valve to seat it and maintain some static pressure in the brake pipes and wheel cylinders when foot pressure is taken off the brake. I also can't seem to find this part if it does need to be replaced. Thanks.

Wow Old-tank, seriously? How do I vent the bellows - poke a hole in the rubber? I just got them good and sealed to keep the dirt and moisture out - lol. I'm not getting a brake pedal return - could this be the cause? Before I rebuilt the booster, I had manual brakes to drive the car if I disconnected the vacuum to the booster. Now, when I disconnect the vacuum, I don't have manual brakes. Is this the hold/lock you are indicating?

Booster is rebuilt and installed. Apparently, I need to make some adjustments since the car brakes are acting like I am pushing on the brake pedal, and the car won't roll. I'll start with brake push rod which may be going in to deep and not clearing the primary cup on release of the brake pedal. When I adjusted all the brakes a while back, I did them pretty firm (book description indicates where you can just turn by hand). But, now that the booster is hopefully working, I can loosen those up a bit. Any thoughts on things to check besides these two?

Sorry, one more question. I had read in a forum post, and the book states this as well, not to use anything containing mineral oil as it will degrade the rubber parts faster. It appears that white lithium grease has mineral oil? Why would Harmon supply this in the brake rebuild kit? Lithium grease typically comprises mineral or synthetic base oil, a lithium thickener, and other additives.

Well, now that I have gone back through the book, it looks like all three are used. Brake fluid on specific master cylinder parts, silicone grease on multiple O rings and other parts and ATF in vacuum chamber, leather ring and felt wick. I'll just follow the book - lol. Amazing how many things are used on this power booster.

Hey Oldtank. Just to confirm, Harmon had white lithium grease in the kit. Is there any issues with using this to coat the parts? The shop manual indicates using automatic transmission. Brake fluid also seems logical. So any thoughts on which is best?

Ok. I have it sorted out. There was a big flat washer in the plug that was stuck and blocking the other parts. Once I got it out, now I see it was worth asking the questions. This was the main vacuum seal area. I've labeled the stack order and the main areas for reference that correlate to the diagrams. Once I finish assembly and reinstall in the car, I'll update this post on the as to if the booster now works.

Yes sir, measure twice and cut once. I've contacted Harmon and they requested pictures. The tech will get back to me Monday that rebuilds old units.

Thanks John. I plan to contact Harmon and discuss the remaining part to confirm if it relates to one of the other year models as a sanity check. I'll post what I learn in case it helps someone else if they run into a similar issue.

Not sure what to do here. The Buick diagram total 9 parts in the master cylinder plug stack up. The Harmon diagram has 10. Mine has seven (laid out in pic in the stack order). I have the one rubber cup and two copper rings left from the Harmon kit. The copper rings can't be in the stack up (though they might be a support as called out in diagrams, but their internal hole is too small for the power piston to go through, so they are eliminated). That leaves the rubber cup. The gap I've left in the stack up sequence order is the only possible location it could go if it's even supposed to go in my booster. However, although it seems to fit it would result in covering the pin holes in the piston bearing (#9 or AZ reference between the two diagrams). The Harmon kit covers 55-59 (I expect some extra/left over parts). The Buick diagram covers 55-56. I believe AV-AY has two versions of the secondary cup retainer and support. Thus, if these are duplicates versions listed between year models, I should have seven parts. Am I way off base or does this make sense? I've added a pic of the stacks as well for reference that also shows the one remaining rubber cup/seal from the Harmon kit. The only logical fit is with the indented side down and the base against the bearing. However, the pin holes are covered, and the orientation is incorrect for the power piston rod to slide in. So, I don't think this part goes in my stack and seven is the correct number of parts. Am I way off base or does this make sense?