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View Full Version : Wilwood master cylinder leaking



drewr
10-16-2023, 12:15 PM
So I'm trying to get my Brake and Lamp Inspection for California, and I notice both my front and rear Wilwood Master Cylinders slowly seeping brake fluid. I know this has come up in many other builds, and I ordered the rebuild kits from Summit. Like others, it seems odd to me that these cylinders would fail so quickly. I only have 30 miles on the car. I took them apart in preparation for the rebuild and have a theory as to why they fail early. The adjusting rod that connects to the piston is facing forward toward the firewall. There is a dust boot, but that rod is a straight shot into the piston. The pedal box and the master cylinders get installed fairly early in the build process. Maybe my shop hygiene isn't the best, but there is an awful lot of dust, metal shavings and general dirtiness that accumulates in the driver foot well. Maybe dust accumulates on the rod and enters the piston and wears the piston O-rings?

Or maybe the O-rings go bad sitting in the box prior to the build?

I inspected the insides of the cylinders and they appear pristine. I wiped them out and will rebuild them later this week. Bummer to have to drain the brake lines and take the master cylinders apart. I have my inspection appointment Friday morning, so hope to have it all ready by then.

Maybe this insight will help. In any case, another set of Wilwoods that failed early for all you data collectors.

Drew

burchfieldb
10-16-2023, 07:32 PM
Be aware, mine looked like this out of the box behind the dust boots. I only notice because I happened to pull back one of the boots.
191240

cc2Arider
10-17-2023, 07:22 AM
Yikes!

I'll look at mine today...

Craig C

drewr
10-17-2023, 10:54 AM
I noticed corrosion on the my pushrods as well. It was outside the boot and nowhere near as bad as your picture. Weird that it would corrode like that.

FF33rod
10-17-2023, 10:58 AM
The master on my hydraulic clutch failed around 500 miles in my '33. I was on a couple of hour road trip to the first big car show. The local shop in the town I was in told me it was the 3rd Wilwood master he'd seen fail in the last 18 months.... A total B**** to replace in its location behind the dash....

Steve