Master Cylinder Replacement

[D-Dubya]

No responses on previous thread so I will try again. Has anyone had to replace the Wilwood master cylinders after the car was completed? My clutch MC failed and I am going to replace all three with Tiltons. Any advice, tricks, special tools, wisdom??

[OB6]

I did the same thing without the body on, so I don't think I have the insight you're looking for. Good move though.

[BornWestUSA]

I just replaced my Clutch master.

I loosened the pushrod jam nut thru the access panel above via the engine compartment with a stubby wrench.

I lowered the fuse box and removed the left end of my dash for access (not a FF dash, custom)

Then remove the reservoir and clutch slave cyl lines from the clutch master, (I vacuum bled out all the fluid via the slave cylinder first)

Then remove the two nuts holding the master to the pedal box

Then unscrew the master cylinder from the clevis, have rags ready, it will still leak.

On installation of the new clutch slave I had to prop up the clevis "level" from above to get it to line up with the master cyl pushrod.

[D-Dubya]

Thanks BornWest,

I had a slow day at work so I went out and decided to make a go of getting the MC's out today. Took me about and hour and a half to get all 3 MC's out with the dash completely off. I did not lower the fuse box, but I can see where that might be helpful. Followed basically the same process you described and, while it was a bit tedious and slow, it wasn't as bad as I had expected. Waiting for new Tilton's to arrive (hopefully tomorrow) to start the process of getting this back together.

A good set of "crowfoot" wrenches would have been very helpful. I would also recommend hiring a very small, very strong trained monkey as it is a tight squeeze through that access panel opening.

I only have about 2500 miles on my MKIV so I was a bit surprised at what I found when I broke down the clutch MC. The seal closest to the pushrod was definitely collapsed and the piston had some major abrasions with matching abrasions on the inside of the bore. The fluid that came out was almost black.

[BornWestUSA]

Please post a follow up, pictures of old and new master cylinders side by side if possible before installation.

The new Wilwood m/c I installed was just a bit shorter from the mounting flange to the slave hydraulic line location of my 12 y.o. one, but still workable.

My old Wilwood m/c's are silver / cast aluminum. the new one looks to be powder coated black aluminum.

I'm curious if the Tilton have exactly the same dimensions as the Wilwoods for future reference.

[Mike.Bray]

The Tilton master cylinders bolt right in. You want the 75 series.

Only real difference is the Tilton is much higher quality than the Wilwood.

[Oshkosh Rob]

When I changed mine out, the line fitting is of different thread, it took a different top cap, and the hose fitting changed from 5/16 to 3/8 which changed bulkhead fitting and fitting on bottom of the reservoir. Chain reaction was a bit more than I expected.

[D-Dubya]

I haven't received the Tiltons yet. I will post when I get them and let you know of any differences.

[RogerDM]

I just replaced my Clutch master.

I loosened the pushrod jam nut thru the access panel above via the engine compartment with a stubby wrench.

I lowered the fuse box and removed the left end of my dash for access (not a FF dash, custom)

Then remove the reservoir and clutch slave cyl lines from the clutch master, (I vacuum bled out all the fluid via the slave cylinder first)

Then remove the two nuts holding the master to the pedal box

Then unscrew the master cylinder from the clevis, have rags ready, it will still leak.

On installation of the new clutch slave I had to prop up the clevis "level" from above to get it to line up with the master cyl pushrod.

Gonna pass this on to a friend. He's taking in this MK4 Roadster project once the new brake pads and tires from 4Wheelonline showed up.

[alexmak]

Thanks BornWest,

I had a slow day at work so I went out and decided to make a go of getting the MC's out today. Took me about and hour and a half to get all 3 MC's out with the dash completely off. I did not lower the fuse box, but I can see where that might be helpful. Followed basically the same process you described and, while it was a bit tedious and slow, it wasn't as bad as I had expected. Waiting for new Tilton's to arrive (hopefully tomorrow) to start the process of getting this back together.

A good set of "crowfoot" wrenches would have been very helpful. I would also recommend hiring a very small, very strong trained monkey as it is a tight squeeze through that access panel opening.

I only have about 2500 miles on my MKIV so I was a bit surprised at what I found when I broke down the clutch MC. The seal closest to the pushrod was definitely collapsed and the piston had some major abrasions with matching abrasions on the inside of the bore. The fluid that came out was almost black.

I'm already browsing amazon looking for those monkeys to help I have the same issue, apparently, and the fluid was pretty black. Not looking forward to swapping that MC.

[cv2065]

I'm already browsing amazon looking for those monkeys to help I have the same issue, apparently, and the fluid was pretty black. Not looking forward to swapping that MC.

One thing to check if the fluid was black. Did you use the correct brake fluid compliant hoses to the reservoirs? If I recall correctly, Rebostar had a failure and found out that the wrong type of hoses were used (fuel hose) and internally disintegrated over time, causing a failure.

[mgibson020]

Another one.

Sold my beloved mk4. 5000 miles, going to good home. Driving away pressure dissapears on the clutch. Naturally he trailors it back to me. I agree to figure it out and fix, right thing to do. Clutch master cylinder, willwood of course. No leaks from slave, no fluid on floor, liquid on bellows side of master cylinder must equal failed MC. Read this thread, ordered crows feet and monkey from amazon. Removing fuse box no problem, dash bit more problematic. Very grateful to the monkey as hands dont fit. About a day of messing about all tolled. Monkey was demanding more fruit at one point that delayed proceedings. Got it done. Blew fuse on dash clock putting dasboard back, otherwise technically straight forward. But what a ***** of a location. But now i have a pet monkey. I donated my body buck, anyone need a monkey?

Prey this doesnt happen to you, or that amazon is out of monkeys. FFR didnt design this thing with maintenance in mind.

Now shes gone. Miss her already.

[BEAR-AvHistory]

One thing to check if the fluid was black. Did you use the correct brake fluid compliant hoses to the reservoirs? If I recall correctly, Rebostar had a failure and found out that the wrong type of hoses were used (fuel hose) and internally disintegrated over time, causing a failure.

The wrong hoses for the kit were in the late 2013 early 2014 time frame. My kit, received Feb 2014 had bad hoses but they sent out replacements, on their own, before I got to it in the build

[cv2065]

The wrong hoses for the kit were in the late 2013 early 2014 time frame. My kit, received Feb 2014 had bad hoses but they sent out replacements, on their own, before I got to it in the build

I think some upgrade them or switch to a hydraulic clutch from the cable and end up with the wrong ones as well.

[ThickCobra]

This topic is very timely for me as my brake master cylinder failed and I need to replace. And of course, the car is complete, except for paint, and I’m not looking forward to working in that little access panel.

I thought I would also take a moment to confirm the type of hoses I am using between the master cylinder and the Titan brake reservoirs. I know it is critical to have the correct hoses. Is the Gates Plant Master 250 black hose appropriate. Or, is there another appropriate hose.

[Jeff Kleiner]

This topic is very timely for me as my brake master cylinder failed and I need to replace. And of course, the car is complete, except for paint, and I’m not looking forward to working in that little access panel.

I thought I would also take a moment to confirm the type of hoses I am using between the master cylinder and the Titan brake reservoirs. I know it is critical to have the correct hoses. Is the Gates Plant Master 250 black hose appropriate. Or, is there another appropriate hose.

Gates says:
"RECOMMENDED FOR: Air, water, oils, antifreeze solutions..."

Given that both antifreeze and brake fluid are glycol based I'd interpret that to mean that hose is appropriate.

Jeff

[JJK]

Great question, as my ASE Master Tech originally failed my inspection because of the Gates Plant Master 250 hoses as he said they were not EPDM and not rated for brake fluid. I did some research and confirmed that these hoses, as shipped from FFR, are indeed EPDM and rated for brake fluid.

[rich grsc]

I have found that most air hoses are EPDM, and work fine for brake fluids. At one time you could buy it by the foot at Lowe's

[JMD]

Make sure the hoses going to the reservoir are EPDM and not just plain rubber hose or fuel line. They will break down and sweat. I wonder if some of the Wilwood MC failures people are reporting have to do with that. Wilwood doesn't send any reservoir hosing with their kits...I bet most people throw in a regular rubber hose and move on. The hoses breaking down would contaminate the fluid and could get into the MC seals. The Tilton MC kit comes with EPDM hose included. I bet doing that alone reduces their failure rates.

[Mike.Bray]

JJ is correct about EPDM hoses being compatible with glycol based brake fluids. The other option is Nitrile (NBR) hose.

EPDM hoses are not compatible with petroleum based products though so don't use it for fuel hose.

[cv2065]

You can buy remote brake fluid reservoir hoses from Pegasus Racing. I used these:

https://www.pegasusautoracing.com/pr...oduct=3575-375

[JMD]

Got my EPDM at the local Tractor Supply! :-D

[OB6]

Got my EPDM at the local Tractor Supply! :-D

Me too. Good price if I recall.

[ThickCobra]

In the fall of last year, I took delivery of my second MK4. At that time the brake hoses provided between the reservoir and the master cylinder were Gates plant master 250. As I’m now replacing one of the master cylinders I thought I’d confirm which lines should be used for the master cylinder hoses. I recently googled Gates plant master 250 hoses and here is their info.

“ black gates plant master 250 hoses are generally not recommended for brake fluid despite being made of EPDM rubber. It is primarily designed for air, water, and light agricultural sprays. While some EPDM materials are compatible with synthetic brake fluid this specific industrial hose lacks the proper ratings and oil resistance, (rated C ) necessary for brake systems, often leading to swelling or failure.”

Factory five sales techs did not know what hose should be used and they were not familiar with the gates plant master 250 hoses that came with my kit. I convinced them to go talk with the shop tech as to what hose they are currently recommending for brake fluid. The labeling on the hose states “SAE J30R 14 T2 1/4inch.” And, their hose does not indicate it is EPDM.

Sometimes something so basic is made so hard to nail down.

I am very familiar with having the correct hoses for brake fluid. On my first build, I mistakenly used fuel line hoses because it was black. It was merely within a few days that the rubber hoses started to break down. I will never make that mistake again. Or I thought.

Thank you everyone for your feedback.

[Mike.Bray]

My hoses are holding up just fine

20220603_140543 (Medium) Rotated.jpg

[CW_MI]

My hoses are holding up just fine

20220603_140543 (Medium) Rotated.jpg

Show off...

[JMD]

Totally overkill...but very nice. Almost a shame to cover that up. If mine looked like that I'd want to see them all the time!

[PMD24]

I recently looked up the EPDM hose that I used and the manufacturers website has language similar to what you describe. One would think that EPDM is EPDM. Hopefully someone with the technical background on EPDM can explain the disclaimer for us.

Pat

[Mike.Bray]

Totally overkill...but very nice. Almost a shame to cover that up. If mine looked like that I'd want to see them all the time!

Thanks but TBH if I was doing it again I would use -4 AN brake hose as it's easier to work with and around.

[F500guy]

I recently looked up the EPDM hose that I used and the manufacturers website has language similar to what you describe. One would think that EPDM is EPDM. Hopefully someone with the technical background on EPDM can explain the disclaimer for us.

Pat

EDPM can have some different manufacture technique that create lower quality. Learned that from a parts vendor when we had a supply of EDPM gaskets in a chemical system that were failing with very short life cycle. I don't remember all the details, just that it is possible.