Wilwood Master Cylinders

[John J Phillips]

There might have been a previous post on this topic, but I didn't see one. If so, I apologize for the redundancy. I have the complete kit with the Wilwood pedal box and master cylinders. I used two CNC reservoirs and stainless steel brake lines. Once installed and the system bled, I kept noticing a small seepage around the bango bolt on the smaller master cylinder for the rear brakes. Not a leak, just a small amount of fluid. They were torqued to specs and tightening and replacing the crush washers did not solve the problem.

I called FFR and they said this had become a common issue and they sent me two new Wilwood master cylinders. The new cylinders have a 90 degree brake line fitting at the back of the cylinder instead of the 45 degree in the middle on the original. Additionally, the hose from the reservoir is now 1/4" versus the 3/8" original. FFR supplied two brake line extensions and a 90 degree 1/8"NPT / 1/4" fitting for the reservoir.

Anyone reading will know the issues involved with this change. I am happy that I saw the leak now and can make the change versus post sheet metal and fuse box installation.

A long winded way to say, check around your bango bolts.

[boat737]

The banjo bolt you are referencing, is that the Reservoir to MC line? or the pressure line out to the wheel calipers? I have a banjo bolt into the MC, and a flare hard line out (Both on top of the MC).

[John J Phillips]

Yes, the reservoir to MC line.

[boat737]

It sounds like I have the one's you HAD, and my clutch MC is what you HAVE now. I just recently swapped out the reservoir to MC rubber lines on all 3 systems. The brake MC's had banjos with barbed fittings and the clutch had a cap with another barb. I got rid of all that and am now installing stainless braided flex line with -03AN fittings on all three: Banjos on the brake MC's and a screw in cap on the clutch.) I haven't filled or bled the system yet with the new banjos, but the old one's seemed tight and dry. (the rubber hoses is what I was worried about.) I should be able to get them filled and tested in the next 2 or 3 weeks and can check for leaks then.

The old setup with the rubber hoses, and the new setup with the flex line.

IMG_0561 small.jpgIMG_0609 small.jpg

[karlos]

I had the same issue when I originally installed my MCs, except in my case it was definitely a leak (enough to end up on the bottom of the footbox). My setup is as shown below. I was able to solve the problem by changing out the banjo fittings and the crush washers. The leak seemed to be between the banjo and the crush washer rather than between the crush washer and the master cylinder. In looking closely at the banjo fittings I noticed there was a lack of a flat surface on which to seat the washer like you typically see on a banjo. My particular fittings had more of a knife edge. And the diameter of the knife edge was very close, if not a tiny bit smaller, than that of the ID of the washer. So what seemed to be happening was that the sharp edge of the banjo fitting was slipping inside the ID of the washer and there was simply no way it was gonna seal like that.

I picked up a couple replacement banjo fittings, but they too had no real flat on which to seat the washer. However, when paired with some thick copper crush washers which were carefully centered over the banjo fitting I was able to get it to seal (second photo). In general I think copper crush washers work better than the aluminum variety like I had in my original installation.

Maybe I had a different problem with the same end result (leakage).

[boat737]

I had the same issue when I originally installed my MCs, except in my case it was definitely a leak (enough to end up on the bottom of the footbox). My setup is as shown below. I was able to solve the problem by changing out the banjo fittings and the crush washers. The leak seemed to be between the banjo and the crush washer rather than between the crush washer and the master cylinder. In looking closely at the banjo fittings I noticed there was a lack of a flat surface on which to seat the washer like you typically see on a banjo. My particular fittings had more of a knife edge. And the diameter of the knife edge was very close, if not a tiny bit smaller, than that of the ID of the washer. So what seemed to be happening was that the sharp edge of the banjo fitting was slipping inside the ID of the washer and there was simply no way it was gonna seal like that.

I picked up a couple replacement banjo fittings, but they too had no real flat on which to seat the washer. However, when paired with some thick copper crush washers which were carefully centered over the banjo fitting I was able to get it to seal (second photo). In general I think copper crush washers work better than the aluminum variety like I had in my original installation.

Maybe I had a different problem with the same end result (leakage).

I know what you mean about the "knife edge" banjo's. I got a nice new set from Wilwood, but they were very thick, and the bolt was too short to properly tighten in the MC housing. I made a trip down to Earl's Plumbing, to get a thinner banjo collar, and all they had were those very thin, knife edge sealing surface banjo's. But, before I left, I asked if, instead of a thinner banjo, they had a longer bolt. Eureka, they did, so I used Wilwood's collar and Earl's bolt. I still have the copper crush washers from the Wilwood set, and the aluminum crush washers from the Earl's set. I'm torn on which ones to use 'cause Wilwood said to use copper, and Earl's said Aluminum. Woe is me.

[j.miller]

I'm a firm believer in the copper crush washers.

[John J Phillips]

It sounds like I have the one's you HAD, and my clutch MC is what you HAVE now. I just recently swapped out the reservoir to MC rubber lines on all 3 systems. The brake MC's had banjos with barbed fittings and the clutch had a cap with another barb. I got rid of all that and am now installing stainless braided flex line with -03AN fittings on all three: Banjos on the brake MC's and a screw in cap on the clutch.) I haven't filled or bled the system yet with the new banjos, but the old one's seemed tight and dry. (the rubber hoses is what I was worried about.) I should be able to get them filled and tested in the next 2 or 3 weeks and can check for leaks then.

The old setup with the rubber hoses, and the new setup with the flex line.

IMG_0561 small.jpgIMG_0609 small.jpg

Where did you find the screw in cap that replaced the cap with a barb? I would much prefer this setup.

[boat737]

I talked to Joshua at Wilwood. 805-384-4181. Part number 220-11910 Here's a better picture. I think it is black anodized aluminum. Some sort of alloy in any case, not plastic. The one I got initially did not have an o-ring, but when I questioned Josh about it, he said it did indeed need an o-ring, so he sent me those after.

IMG_0606 small.jpg

And per Bat's comment above, I think I'll be using the copper crush washers on the banjo's on the brake MC's.

[John J Phillips]

Okay - I am convinced to try and salvage the existing master cylinders. I am switching to the AN fittings and hose. Here is a question - when looking for copper crush washers, I came across the "Stat-O-Seal from Earl's Plumbing (Really). Has anyone used these?

The following is the information from the website "The Stat-O-Seal is very simply the best sealing washer available. It consists of a synthetic rubber O ring mechanically locked to the I.D. of an aluminum washer. When tightened, the O ring is compressed, forcing the sealing surfaces around the bolt shank. They will form a positive seal over a temperature range of -85° to +450° F. They provide the advantages of an O ring type seal without the necessity of machining O ring grooves into the part. In any application where you are now using a copper or aluminum sealing washer, the Stat-O-Seal will do a better job."

Sounds too good to be true, but perhaps someone has experience with them. I have ordered a couple to see what they look and feel like.

Thanks for the feedback and help with this little hiccup.

[boat737]

I would make sure that "synthetic rubber O ring" is brake fluid compatible. The banjo's I got from Wilwood had copper crush washers in the kit. I would bet they sell just the crush washer.

[edwardb]

I get it that there have apparently been issues with the banjo connections and crush washers for the reservoir feeds. Enough that FF chose to use a different setup. But many hundreds of kits have been successfully built with the previous setup. Keep in mind it's just a gravity feed. And a pretty low pressure one at that given the relatively small amount of fluid in the reservoir. Not a high pressure banjo connection like often used on calipers. If the mating surfaces are all clean and flat, no reason IMO that these won't seal. Generally it's not a good idea to re-use crush washers, so if necessary to disassemble or rework, then get new ones. Maybe that's behind some of the issues? I also agree copper is preferable. They're available at any parts store and not expensive. I would be very careful introducing anything different into the mix. My kit came with copper crush washers. Once installed and tightened, I haven't had any issues at all. Not on the road yet, but system is fully bled, has been extensively tested, and several go-kart drives. If they were going to leak, they would have by now.

[karlos]

I would make sure that "synthetic rubber O ring" is brake fluid compatible. The banjo's I got from Wilwood had copper crush washers in the kit. I would bet they sell just the crush washer.

Very good point. I looked into Stat-O-Seal's when I was having my leakage issues. Was never able to confirm the specific rubber compound, but there is a fairly narrow range of materials that can coexist with brake fluid. My guess is that the Stat-O-Seals are nitrile, which is unhappy in brake fluid as shown below. In the end I went with the good old fashioned copper washers I mentioned above. Got 10 of them at Summit for about $6: https://www.summitracing.com/parts/urr-brc137