Technical Wheel cylinders

Okay just wanna make sure I am not doing something wrong.

I got 3 different driver side rear wheel cylinders from a pretty popular vendor of early ford parts.

The first had a broken piston- they sent a replacement, and I purchased a back up


the second and third leak. Badly. I have not called on these yet.

am I doing something wrong ? The only thing I had to do was spin the piston to line up with the shoes. Outside of that they were right out of the box.

I finally had to put my original ( from napa ) on and that did not leak.

again did I do something wrong by turning the pistons ? Is anyone else having an issue like this? Am I crazy ?!? ‍♂️

Any input is appreciated!!


- Jon

 

This is the kind of junk we get now, even from NAPA I've gotten wheel cylinders that leak, I've got to the point where I send out the ones I have and have them sleeved.
No you did not harm anything by turning the piston.

 

Clean your stock ones with a brake cylinder hone and install new cups. They are available in any size.

 

Wheel cylinders are dry or the lube has dried up.
It's always good practice to pull apart a new set of wheel cylinders and inspect the bore, pistons and cups for any irregularities and to check for correct lubrication. A dry cylinder will seize and/or leak.

 

Did a complete overhaul of the brakes, I wondered about that, they'd been on the shelf for a while. So pre-filled the wheel cylinders with brake fluid and let them sit for a day or two, on the idea maybe the rubber parts would absorb some or swell. Good idea or not, dunno, but it made me feel better about the whole operation.

 

you shouldn’t have to, but like @Truck64 said. How long have they been sitting on the shelf? Defiantly good practice.

how many new cars ( go back 20 years ) come with wheel cylinders ?
So for a part for an old car to be sitting a year or more is not a surprise .
I got rear shocks for my 64 merc I swear the boxes where 30 years old

 

I used to have a large inventory of new WC kits, I went through them over the years and finally chucked the odd ones. Now the kits are more than the actual cylinders. I got my new cylinders for the Ford, name brand made you-know-where for under $6 each at Rock Auto. Going on 5 years, no leaks.

 

I dont know why they leaked...I've had better luck than that.

But I also just put a new kit in the old ones whenever I can. And I have an old bottle of this stuff, which I use every time. It's kind of like honey....but not sticky.

 

You didn't tell us what kind of brakes, so we are all guessing.

On old Ford brakes (39-48) it is common for the repro cylinders to have the entrance hole drilled slightly skewed more than Ford did. It lets the fluid get past the lip of the cup when the cup is pushed too far towards the center. To keep them from leaking on first install, make sure to pull the cups and cylinders as far out as possible on assembly, and have the side adjuster cams kinda adjusted "out". This keeps the pistons from getting pushed too far into the cylinder, and letting the fluid escape past the cup lip.

 

I was told not to use Vaseline on rubber as it is petroleum based and will break down the rubber. Found that out when I started using it on the rubber seal on my pool pump skimmer basket. It was harder than hell to turn the lid off the pump so I started to coat it with Vaseline only to discover the gasket started to breakdown. Went to the pool place to get a new rubber seal and the guy there told me to use olive oil on the seal.

 

Thank you, Olive oil is less greasy and cleaner.

Once the stainless sleeves came out, I didn't need to use grease or any other petroleum product..

 

Anything petroleum based is a terrible idea in a brake system.

I too rebuild them, mostly because I can.

 

OP, you are NOT saying that the pistons were in backwards??
if so, God save us!

 

Basically what I had to do in the 70's for my Studebaker - buy the rebuild kits for both the master and wheel cylinders.