buickbrothers Posted March 13 Share Posted March 13 I've pulled the brake booster out and I'm working to restore. I'm stuck getting the cylinder housing to separate from the hydraulic cylinder. Is this just an "O" ring pressed fitting? I can see the cylinder plug will require a special tool to get off (yee haw). Does this need to come out first (book seems to indicate this comes out after you separate from the cylinder housing). Any thoughts on how to separate the two - this baby is not budging if I try to turn the housing by hand after removing the 4 bolts (Delco Moraine Power Booster). Link to comment Share on other sites More sharing options...
buickbrothers Posted March 13 Author Share Posted March 13 Never mind - I finally got it separated. Had to put it on my press. Rust and gasket glue had them cemented. Now the challenge is getting the cylinder plug to unscrew since I don't have the special tool to use for the removal and I see rust on the underside of the plug where it screws in. Any tip's/trick's would be appreciated. Link to comment Share on other sites More sharing options...
Fr. Buick Posted March 13 Share Posted March 13 Heat and an impact wrench, but don't overdo it. I had one develop cracks in the housing from my efforts. Link to comment Share on other sites More sharing options...
buickbrothers Posted March 14 Author Share Posted March 14 I've got everything apart, cleaned and working on swapping the new parts with the old. I'm struggling in one spot as there seems to be a part that came in the Harmon kit that wasn't in my booster. Maybe this was worked on before or maybe it doesn't go on this model. I'm trying to correlate between two diagrams. The first was posted in a forum discussion but it didn't have the part list/descriptions to the references. Does anyone have the parts list that goes with this? The second diagram came with the Harmon kit. My problem/confusion is that I don't have items 3, 4 and 5 per the Harmon diagram - wasn't in my master cylinder plug stack up. Everything from 6 on was staked in that order. There is one rubber/seal part left in the Harmon kit that concerns me which I believe is item 3 - Vacuum Seal. It looks like a cup and the shaft goes through it. When I look at the first diagram, I believe it would be AX. Both diagrams have stack-up differences. Thus, I'm not sure what to do as I have matched up what was in my master cylinder plug stack up. The part list/descriptions for diagram would be helpful if anyone has it or the stack-up for master cylinder plug on a 55 Delco Moraine would be awesome. Thanks. Link to comment Share on other sites More sharing options...
JohnD1956 Posted March 15 Share Posted March 15 1 Link to comment Share on other sites More sharing options...
buickbrothers Posted March 15 Author Share Posted March 15 Thanks John! I’ll dig through and see what I can determine. Really appreciate it! Link to comment Share on other sites More sharing options...
JohnD1956 Posted March 15 Share Posted March 15 My pleasure. Good luck Link to comment Share on other sites More sharing options...
buickbrothers Posted March 15 Author Share Posted March 15 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? Link to comment Share on other sites More sharing options...
JohnD1956 Posted March 15 Share Posted March 15 These pictures are in the same November 1, 1960 parts manual. It might be the extra part you have is applied in one of these two other assemblies, but not in yours? Note the Hydrovac power brake unit does not have a year assigned. And the next image was for a 1960 assembly. Since your kit supposedly covers up to 59 I left the 1960 unit out of this post. Link to comment Share on other sites More sharing options...
JohnD1956 Posted March 15 Share Posted March 15 But here is the 1960 assembly in case anyone is curious. 1 Link to comment Share on other sites More sharing options...
buickbrothers Posted March 15 Author Share Posted March 15 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. 2 Link to comment Share on other sites More sharing options...
JohnD1956 Posted March 15 Share Posted March 15 @buickbrothers thats a good idea. Those explosion diagrams look kind scary. It looks easy to make a mistake. Link to comment Share on other sites More sharing options...
buickbrothers Posted March 15 Author Share Posted March 15 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. 1 1 Link to comment Share on other sites More sharing options...
buickbrothers Posted March 17 Author Share Posted March 17 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. 1 1 Link to comment Share on other sites More sharing options...
old-tank Posted March 17 Share Posted March 17 Thanks! Use brake fluid to lubricate as an assembly lube if you are going to put it together and put into service right away. Otherwise use Sil-glyd as an assembly lube (this will prevent rusting of parts exposed to air. 2 Link to comment Share on other sites More sharing options...
buickbrothers Posted March 17 Author Share Posted March 17 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? Link to comment Share on other sites More sharing options...
buickbrothers Posted March 17 Author Share Posted March 17 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. Link to comment Share on other sites More sharing options...
buickbrothers Posted March 17 Author Share Posted March 17 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. Link to comment Share on other sites More sharing options...
old-tank Posted March 17 Share Posted March 17 1 hour ago, buickbrothers said: 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. Ask them. Maybe the rubber they use is compatible? 1 Link to comment Share on other sites More sharing options...
buickbrothers Posted March 22 Author Share Posted March 22 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? Link to comment Share on other sites More sharing options...
old-tank Posted March 22 Share Posted March 22 The corrugated bellows at the front of the booster needs to be vented if it's sealed too good the brakes hold lock until you shut the engine off and it bleeds down. Link to comment Share on other sites More sharing options...
buickbrothers Posted March 23 Author Share Posted March 23 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? Link to comment Share on other sites More sharing options...
JohnD1956 Posted March 23 Share Posted March 23 6 hours ago, buickbrothers said: When I adjusted all the brakes a while back, I did them pretty firm (book description indicates where you can just turn by hand). Once they are that tight the book also says to back off a bunch of notches. I forget how many. But one thing that has seemed to help a bunch of us is to do the anchor pin adjustment. 1 Link to comment Share on other sites More sharing options...
old-tank Posted March 23 Share Posted March 23 A short piece of brake line between the shaft and the end of the boot will vent it and get your brakes working as designed. 1 Link to comment Share on other sites More sharing options...
buickbrothers Posted March 23 Author Share Posted March 23 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. Link to comment Share on other sites More sharing options...
old-tank Posted March 23 Share Posted March 23 When I replaced the tattered boot on my working power brakes, the first time I applied the brakes they stayed applied until a few minutes after shutdown. Venting the boot and it worked as designed again. If that does not work for you call the supplier. Link to comment Share on other sites More sharing options...
buickbrothers Posted March 24 Author Share Posted March 24 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! 2 1 Link to comment Share on other sites More sharing options...
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