The Cleveland brakes use a small hard rubberry black piece to protect the caliper bleeder valve from dust and debris. They seem pretty expensive to replace through the usual parts supply chains and I seem really good at losing them. Has anyone found a good source for these other than through the Cleveland part number? Like maybe a 50 pack from Mcmaster Carr or something?

This is what they look like:
https://photos.app.goo.gl/1KYJ9VDAyuwxkGpc7

Sounds like you already knew where to look. Looks like 1/4” from that picture?

https://www.mcmaster.com/product/6448K77

https://www.mcmaster.com/products/rubbe ... ound-caps/

Unfortunately they don't have a datasheet for the covers, so I'm not sure about their resistance to fluid. I can order a couple different sizes and test but was hoping someone else might have already done that, either from them or from another source.

The Mcmaster Carr parts show as EPDM which appears to not be compatible with MIL-H-5606 or ATF. A Google search under "brake bleedeer caps" brings up many results, might be something among them that would work???

From site: https://mykin.com/rubber-chemical-resistance-chart-4

Preferred materials: Nitrile (Buna-N), Viton, Fluorosilicone (not Silicone)

Fair materials: Neoprene, Polyacrylate, Hypalon, Polyurethane


Amazon showed some PVC caps on above search, might be satisfactory???

jaredyates wrote:Unfortunately they don't have a datasheet for the covers, so I'm not sure about their resistance to fluid. I can order a couple different sizes and test but was hoping someone else might have already done that, either from them or from another source.

You’re right, funny that “chemical resistant” doesn’t include hydrocarbons like gas or oil haha

Hardware store, auto parts store, etc, common caps. As mentioned, there are different material types.

I'm back with more data to report. I ordered some of the following two from Mcmaster Carr:

Round Caps for 3/16" to 1/4" OD, 1/2" Inside Height, Red 9753K318
Round Caps for 1/4" to 5/16" OD, 1/2" Inside Height, Red 9753K326

Unfortunately I don't have a new and unused Cleveland cap to compare in a photo to a new and unused MMC cap, but here are some photos comparing a used Cleveland cap and a new MMC cap:
https://photos.app.goo.gl/SKqGHPLZqXS7XqFm7

The smaller caps look too small to me to go onto the bleeder fully. I installed one of the bigger caps and will see how it holds up. I think it is still snug enough that it will stay in place. They are available in black, but I think the red will work better if I drop it in the grass like I usually do.

Buying a 100 pack of the red ones costs the same as buying a single cap with the Cleveland part number.

Another big unknown is solvent resistance, but honestly, I don't find that the Cleveland caps are all that great either. They get hard and lose their rubbery feel in a very short time, but I don't know if this is because of the fluid.

I'll try and remember to come back and report in another few months.

Jeez how often are you bleeding your brakes!? Seems odd to be concerned about loosing a dust cover while bleeding your brakes in the field...

jaredyates wrote:They are available in black, but I think the red will work better if I drop it in the grass like I usually do.

Use your Parker CMM (available free) to look up the p/n and order one from Spruce.

Well…if you have 100 of each can I buy 10 of the red to reduce your cost….feel free to mark up…!

Sorry for the late reply... I was helping test some prototype brake components and was draining the fluid several times. But also my hangar floor is "the field" these days, so even in the best of times, it's sub-optimal.