Wilwood Master Cyl Issue

[Dave Harmison]

I replaced my master cylinders over the winter and noticed the caps leak. I took the masters off the car and found that the threads cast into the body are parallel to the top, not spiraling down like they should. Multiple calls and emails to Wilwood isn’t getting me anywhere. Any body else find this?

[DaveW]

I replaced my master cylinders over the winter and noticed the caps leak. I took the masters off the car and found that the threads cast into the body are parallel to the top, not spiraling down like they should. Multiple calls and emails to Wilwood isn’t getting me anywhere. Any body else find this?

Not that I've ever seen that before, but I can envision a cap with short angled thread sections working with those parallel ridges.

The parallel ridges are obviously not continuous around the body - that's what may allow my idea to work. Short angled ridges on the cap might, properly designed, wedge the cap seal into firm contact with the top of the body with a quarter turn or less.

The fact that it's leaking, however, means something is amiss, but I would hope it's not the basic design at issue.

[Rick Kirchner]

snap top instead of twist off???

[DaveW]

A question - is the leak at the seal, or from the cap vent? Short masters like that often leak from the vent - that's why the silicon bellows were used. I also used fuel cell foam in the reservoir to minimize sloshing and leakage.

[Dave Harmison]

Definitely leaking from cap around edge. Wilwood sent me replacement seal/diaphragm. No help. Then they sent caps with a funky thread form, but still no joy. Girling has proper thread lead. Old Wilwood have proper thread. These, junk.

[DaveW]

Definitely leaking from cap around edge. Wilwood sent me replacement seal/diaphragm. No help. Then they sent caps with a funky thread form, but still no joy. Girling has proper thread lead. Old Wilwood have proper thread. These, junk.

That's not good - Wilwood has recently come out with some really nice stuff. This is not a good sign. Wonder how they got designed that way and why their QC didn't find it.

[Dave Harmison]

I bought Wilwood because I thought I’d buy American. A guy I talked to let slip that the castings are off-shore.
Having been on factory floors as resident engineer, I’m sure the print was misread or ignored when they made the casting die.
I had hoped Wilwood would exchange for good parts. Instead, Wilwood wants to give me a discount to BUY replacements.

[DanW]

Yes, casting are from offshore. Machining in US, Camarillo, CA.

The "threads" aren't really threads. I think the top was supposed to use a rubber snap cap. We had the same issue. Called them and they offered credit to buy something else. Bought a set of Tilton masters instead.

[Dave Harmison]

There are two “threads” on one side and one on the other, just like Girling and older Wilwood, just not sloped to have a thread lead. If it was supposed to snap, the grooves would be the same distance from the rim and symmetrical, which they aren’t. The replacement caps Wilwood sent me have a very broad groove to try to bridge the cast thread despite not being pitched. This leaves the cap pulling down on two or three points, no broad contact area, and it leaks to the point it’s unsafe to use. Almost ran dry in last race.

I appreciate the comments. Just really, really disappointed with the product and service.

[CGOffroad]

Bear with me on the explanation, but it could be relevant as this is a massive reality in other industries...

Beginning of summer I had a NEW air conditioner unit to just stop working. This is in Arizona, so we pay to be on a contract which will get a tech out in case of emergency. We had a tech out the next morning. He gets the machine running and has some interesting information for us. He shows us the picture he took of serial number plate and it shows a construction date of late 2021. The problem ended up being a circuit board that he replaced. He then tells us that we can expect further failures and that 80-90% of the calls his company is going to are for units built in 2020-2022 range. The logic is that things built during this time were assembled by anyone that would actually show up to a job and work. Here is a word you may have never heard.... COVID

Two weeks ago we had a Polish technician on our ship to repair the RADAR. Our ET's have been onsite trouble shooting this unit for over a year. They have replaced basically every component in the array that is mounted on the mast. In the end, the tech got it working and his diagnosis may sound familiar. He told us that before coming offshore he looked through all replacement parts in the warehouse in Poland and traced purchase records for all of them. He would not take parts from warehouse unless they had been on the shelf since Jan 2020 or longer. He said the same thing as AC tech. They are experiencing problems with any and all parts made during COVID.

I am not saying this is the problem with your master cylinder. But, at one point, I remember our race group needing something from Wilwood and there was a significant wait as parts weren't available during COVID. What if someone in the factory was just putting the wrong lids on master cylinders that were coming down the line? Occam's Razor.

[BeerBudgetRacing]

Yes, casting are from offshore. Machining in US, Camarillo, CA.

The "threads" aren't really threads. I think the top was supposed to use a rubber snap cap. We had the same issue. Called them and they offered credit to buy something else. Bought a set of Tilton masters instead.

The "threads" aren't really threads. I think the top was supposed to use a rubber snap cap. We had the same issue. Called them and they offered credit to buy something else. Bought a set of Tilton masters instead.[/QUOTE]

Are we sure Tilton castings are onshore? They're in a relatively small shop - so the don't cast them in Buelton.

As for Wilwoods - I have a set of the WLD20s and like them.

Just really, really disappointed with the product and service.

I have a Wilwood master on a Z-car that was faulty when delivered so I walked in their door with it.
A good unit arrived in 2 days.

Send it back and tell them to fix it - whether you use it or not.

[pooch776]

I had the same issue with a .75 clutch master. I installed a new Wilwood master cylinder and the cap leaked on a freshly restored Lotus FF. I tried various spare caps I had thinking it was the cap. No joy. I finally rebuilt an old Girling master and installed it. I have not had any issues since.

Good Luck, Joe

[Dave Harmison]

CGOffRoad- Yep, the rounded cap is what the masters came with and the more squared off is the replacement cap Wilwood sent me, neither actually prevent the fluid from sloshing out.

[teamwisconsin]

Wilwood has done an excellent job of marketing to the SEMA crowd, and making "designer imposter" parts at a much reduced price to the parts they are copies of (the Girling master, the PFC ZR55 calipers, etc). The reduced price could be explained as they haven't had to pay for the engineering or design as they are basically copies, or it could be cost cutting shortcuts. We all have to draw our own conclusions I suppose. When it comes to stopping a racecar for one of my clients, I would not put a car on the track with a Wilwood part on it.

[Dave Harmison]

Is there an American alternative or is that like trying to find American made sneakers?

[alangbaker]

I replaced my master cylinders over the winter and noticed the caps leak. I took the masters off the car and found that the threads cast into the body are parallel to the top, not spiraling down like they should. Multiple calls and emails to Wilwood isn’t getting me anywhere. Any body else find this?

What was the part number?

Just curious.