During my drum brake replacement I had pushed the wheel cylinder out to far so that one side leaked brake fluid following. I had a "new" spare so swapped it in but that one leaks too, $25 from the local parts shop. (The Toyota Aisin is $50 from the dealer.)

My question/s: how fragile are the seals on these pistons? The bore is clean with no obvious scratches or gouges to leak fluid. The seal on the piston looks clean with no obvious marks either. I've pressed it back in but IDK. I hate to re-install it and find that it leaks and have to do the task again.

Can I use an HNBR or EPDM O-ring in place of the originals and still get a good seal? I have to take a cylinder apart and measure the specs so hoping it is an available standard size.

Any thoughts to what can be done?

 

$50 for the Aisin is well worth it, unless it is very old stock meaning the rubber is not in the best condition. Wheel cylinders are notorious for leaks I owned a 1977 Celica lost track of many times I had issues.Would be cool if you could find a generic seal made from better material.

Is a disc swap feasible? Drum brakes are one of the worse inventions in the history of the human race.

 

A disc swap would be cool but not $ practical. This task required something more wallet friendly so bought a non Toyota part. In the end it didn't work out so that was a gamble on my end and lost. Aftermarket wheel cylinders these days are a 50-50 shot. Saw a You Tube video of a guy that honed the cylinders getting good results. I'm not about to buy a $25 hone and put more labor into some low end part. (Some people like to do this but I don't.) I've already lost time and the car has been down 2 days while the parts parts come in. Frustrating. I'll get some measurements and see what may be available in HNBR or EPDM.

Toyota does have seal kits for certain applications but not for this one. Speaking of '77 Celica, the next brake task will be for the '80 Celica. Toyota does have a rebuild kit available for it.

 

I couldn't find part numbers to check because the places I looked don't go back far enough. When I used to rebuild cylinders I didn't do anything to the bores just replaced the rubber, I'm sure polishing them would help.
Same one I used way back when.

You must have a fun time trying to get parts I had trouble 15 years ago when I owned my TE27 Corolla.

 

I like those TE27 Corolla's, that old school body style is memorable for me of Toyota.

Parts are tough for sure. Stocked up on some but have used them over the years. The whole brake system has to be gone through. The rear wheel cylinders finally leaked out and the flex hoses to the rear drums also cracked open. Have hoses and fortunately those wheel cylinders were used in enough Toyota that the rebuild kit is still available. My neighbor gifted me some of his auto tools and among them a small cylinder hone. So I hope to resurface the ones in the Celica. Lots of work and $ so this is a long term project.

 

My car looked almost the same as this (trim and lights were the older style) but in blue, same colour as the air cleaner. For some reason every car had that colour air cleaner no matter the exterior. Happy to see the owner kept it that way.

I'd love to see pics of your car.

 

That's a nice well maintained Corolla!

One of the Toyota parts guys has a similar '80 Celica notchback. His hybrid 20R/22R ported-polished and OS valved head along with to other engine word was putting out 196HP at the wheels with the dual Mikuni's. Not particularly fast at 13's but compared to stock, that's quick. He has the Webers on it because the Mikunis are to much $ and he doesn't have some of the tuning parts he needs to run them. It will do 10 MPG in this build...ouch!

This is mine:

 

Love it. That generation of Celica angered the purists mostly in Japan they didn't like the styling at all. Hybrid R engines are amazing I know a guy that has one in an '87 pickup that sucker rips, no traction at all it's 2WD.

I had dual side draft Mikuni's on my TE27 for a short time the most troublesome carburetor I have ever worked with. I could never get it jetted right it would either pull nice at high revs or idle nice but have no power. I gave up.

 

I have popped out many leaky clutch and wheel cylinder pistons, if you clean them with a tooth brush and brake fluid and put them back in they rarely leak. They just need a little cleaning and re seating generally. Just be careful when you pop it back in so you dont bend the lip over.