Here is a complete unit taken apart to clean and also replace the power piston seals which usually cause an internal leak.
Main Metal O Ring Retainer is removed using an awl into the angled end of the retainer clip and prying it out to reveal some space, it's about 1/8" in the groove so you have to pry a bit to get a gap which you can stick a thin small screwdriver into to start the clip removal process and work your way around it to get it off.
The next step was to remove the Power Piston from the bore.
The book says you can use compressed air into the side fitting ports that will pop it out but I just used a large screwdriver through the brake pedal arm hole and a block of wood against the body of the bore and popped it out with controlled leverage it wasn't that hard.
Here is what comes out and note the 3 O rings on it to be replaced.
Close up of the power piston body.
Power Piston Body with 3 O rings removed and cleaned with denatured alky. and a clean shop paper towel by hand.
Note: Do not use anything but a wooden rod or stick on this stuff it's all aluminum, to get the bore clean I used a dowel and the denatured alky. on the shop paper towel you might get away with a decent paper towel such as Bounty or a clean thin shop rag. Finger nails work good through the paper towel soaked with denatured alky. to remove the tougher varnished stains and deposits.
NO MINERAL SPIRITS OR ANY PETROLEUM BASED PRODUCTS CAN BE USED!!!
Here is the bore edge showing some deposits and varnish pre-cleaning. Explains why the end O-ring can sometimes leak and let some brake fluid into the car near the brake pedal.
Here is a look down into the bore (as best I could get) and showing the dirty fluid residue and some deposits, but the bore looked great after cleaning.
And yes there are more parts removed that go into the bore, next post will be pics. of the Reaction Components that slide into the Power Piston.
Here's the bottom of the Reaction Component assembly it's a spring seat that goes into the bottom of the bore shown last post, uncleaned.
Here's a dark picture but it shows the middle of the Reaction Assembly and it's two seals one a pump type seal and the other an O ring, not replaced but cleaned up with denatured alky. for replacement, lubed with brake fluid as the tapered pump type seal fits into the bore and needs DOT 3 lube to make sure it doesn't fold over and get ruined when you put it back together.
If anyone knows the part numbers for those seals or where you can get them please post up the info.
Here is the complete assembly of the Reaction Components cleaned and lubed with DOT 3 but not serviced in any other way.
And an end view of the assembly that goes into the Power Piston towards the top of the bore.
Here is a better close up picture of the Reaction Component seals.
One a pump type tapered and the other an O ring.
Any additional info. is appreciated as to size type and part number and availability.
Here is an end view of the Power Piston the larger part with the 3 O rings on it we are replacing. It shows the brake pedal rod attachment point and some varnish to be cleaned off, I didn't take that apart.
Here is an internal piece that kinda fell out of the reaction components while I was cleaning it.
No seals or anything but there is a rubber disk that goes on the end of the multi-grooved end. It is the reaction disk. No attachment parts it just goes up into the bore and I put it back in there the way it came out, attached with some DOT 3 lube after cleaning the aluminum assembly thoroughly with denatured alky.
Disk goes on the right end of the part and up into the assembly. Don't have the picture of the disk it's just like a rubber ring about 3/32" thick just make sure it's in place after cleaning.
The seals are all discontinued. The 3 o rings on the power piston may be able to be sourced. They are usually in one way or another the problem. Ive rebuilt at least 10 of these and ive noticed there are 2 different piston designs. Im sure the seals are used somewhere else and could be sourced if you knew someone that worked at cardone of one of the big reman companies. Taking the pistons apart wouldnt be too bad
Here is one of the dowels and a shop towel used for initial cleaning of the bore. When mostly clean finish with one clean towel and the alky.
Here are some other dowels and a toothpick used to clean one of the O rings and its' groove I wasn't replacing. Stainless pan with denatured alky. to soak the power piston assembly in works well.
Used the bulb for squirting den. alky. into holes and paths the brake fluid goes in.
The seals are all discontinued. The 3 o rings on the power piston may be able to be sourced. They are usually in one way or another the problem. Ive rebuilt at least 10 of these and ive noticed there are 2 different piston designs. Im sure the seals are used somewhere else and could be sourced if you knew someone that worked at cardone of one of the big reman companies. Taking the pistons apart wouldnt be too bad
True on the Piston Design. If you bought the GM PM rebuild kit it had both in them. Somewhere in my parts bin I have an old rebuild kit.I'll dig it out and photo the 2 pistons. As I recall they were not interchangeable.
The seals are all discontinued. The 3 o rings on the power piston may be able to be sourced. They are usually in one way or another the problem. Ive rebuilt at least 10 of these and ive noticed there are 2 different piston designs. Im sure the seals are used somewhere else and could be sourced if you knew someone that worked at cardone of one of the big reman companies. Taking the pistons apart wouldnt be too bad
i'll make them available at a super fair price anlog with detailed pics and tips on how to do this-------along with some tricks that i have learned that solve problems that aren't covered in the kit instructions .............RC
anything is rebuildable--------many industrial machines use hydraulic accumulators-------in one of my factories the injection molding machines use accumulators that are rebuildable--------they are rather large ie nearly 4 feet in length and cost thousands of dollars------they simply unbolt apart and the rebuild kits are "economical" at least compared to a new unit------the PM units could be repaired------but at what cost-------if you could cut it open like a torque convertor-------glue in a replacement rubber diaphragm-----charge it with replacement nitrogen and then somehow reweld it together without ruining the bladder from heat you would be OK---------along with a jillion other Gn parts i have tucked away hundreds of old accumulators instead of throwing them away-------maybe someday but i'm not holding my breath!!!!!!--------good luck for now..............RC
