Front wheel nut on Twin Leading Shoe cars = 1 1/8th inch?

I know I have a 1 1/8th socket somewhere.  Of course this is the first time I have needed it, and I can't find it...

Yup Still in KC.
i posted a message to your thread on 16v recently too

Thanks Kelly, I'll keep that in mind.  Are you still in KC?

I was getting discouraged until Minimike said he used a block of wood.  The Haynes manual says I had to leave the piston sicking out 8mm.  

I pushed the piston in with my arbor press, and the put a block of wood over the dust seal retaining ring thing and pressed it in also.  Now I just have to order one more set of seals since I ruined one other one...

Metalwrite-
If you hose them shoot me a message, I have several sets of 8.4 calipers i am going to sell at some point. They are off of low mile Japanese minis.

I pump the pistons out with a grease gun, trapping one and then the other. I then separate them and wash them out completely with brake kleen and compressed air. 


I use a vice to press the piston back in, lubed with brake fluid, and keep it paralled to the bore. And I use a block of hardwood to tap the seal ring in place with a hammer on the wood. This keeps it flat too.

Ok, I can't get this metal ring in place for the life of me.  Already ruined 2 of them...

Either of you guys want to loan (rent?) me your special tool?  Promise not to hold it hostage.

Short of that, any tips?  Do I lube it up?  Go in with no lube?  Push hard or soft?  Light a candle to try to get the caliper in the mood?

Well, like I said, I put the wrong seal in and had to remove the piston again.  I used some pliers on the old pistons, and just pulled them out, not afraid to mar them.  When removing the new SS piston, I tried gently with the pliers and quickly decided that wasn't going to work.

So I decide to just put a little air into the hole that goes to the other caliper half..  Literally shot that piston 30 feet!

So like, I will no longer use that method.  And definitely not for a caliper full of fluid, because I don't want old brake fluid over everything in the garage...

Also, gentlemen, thank you for the replies!  I'm well on my way to getting these calipers completed.  Have to find a good solution for the dust seals yet, and I might powder or paint..  

While it's easy to hand in a workshop, using compressed air to move things like you describe is a particularly bad idea.  The stored energy in air is phenominal and can lead to a bad accident in the blink of an eye.  We had an incident at work a few years ago that only involved 8 psig but could easily have been fatal had the object landed in a different direction...

I use an old master cylinder and a bit of brake line to use fluid to push out the pistons in a safe and controlled manner.  Push out the one opposite the threaded hole first, disconnect, and then knock out the easy side.

This can also be done on the car before removing the caliper completely as described in the Leyland manual - pressing the brake pedal gently is a shed-load safer than hooking up an airline !

Yes. I'm on the take them apart team. As mentioned a long punch will remove one piston though the hose threaded hole. I place the other half in a vice with a little space and use air pressure to push the other piston out. Once it starts moving I back the vice off to allow it to pop out. Beware unrestricted it can come out like a bullet. I also have machined a couple of alloy rings which support the dust seal retainers as pressed in place. I glass bead my halves, use a small flapper sanding wheel to brush up the bores and a dentist pick to insure the seal grooves are clean. There is a stepped groove for the main seal which twists the seal. While I have bought and have in stock the half seals I have never replaced one. I carefully remove them place in plastic bag till job is complete. It is very rare that the pistons have not started flaking chrome. SS pistons are a good solution. I have rebuilt vintage 7.5 brakes and after really tough weekends changed out the seals and the SS pistons always look good. I have though about rebuilding several sets of 8.4s for the shelf. Last time I did that the were boxed and on the shelf for years. Steve (CTR) 

IMO only a masochist would attempt to rebuild these calipers without splitting them. Regardless of the Haynes manual's blurb.
The dust seal retainers are fragile and easily bent. I made a tool to press them in straight without damage.

Oh, I see our host sells a seal that goes between the calipers, part 17H7679

If you've split them before removing the pistons, you're in trouble as you'll only be able to remove the one behind the hose union - a parallel punch through the hole will knock it out.

Splitting them is far from the doom that Haynes would have you think.  There's a good ste-by-step article on rebuilding them in Mini Magazine from September 2014 issue 229 - Digital magazine
Cooper S calipers are essentially the same to rebuild as the later 8.4" versions, so don't worry about it being "wrong".

17H7679 are the caliper o-ring seals.

GRK5008 are the seals.
114713 are the stainless steel pistons.

Rookie question, I'm sure this is covered on here but I do not see the "search forum" button..  Probably blinded by 15 year old brake fluid.

So, I have a pair of calipers that I am rebuilding, and for the first one I went ahead and separated the caliper halves.  Then I checked the Haynes manual, and it says not to attempt to separate the two halves.  Crap.  Saw bolts, removed them.  Was this a grave mistake?

On to the seals.  The seals are clearly 2 different sizes, and it appears that the thicker on is the one that goes in the inner groove, and the thinner one is the outside seal that sits under the little retainer ring type thing...  Of course I got the piston in place with the thinner seal on the inside before realizing there were 2 different sizes...  So I took it out, put the thicker one inside, and now can't really get the piston in place..  Is it incorrect to work the piston in with a C clamp?  I am lubricating everything with brake fluid as the Haynes manual suggests..

Perhaps there are other tips I am missing here.  I'm using a new seal kit, and also new stainless pistons..

Thanks!