BACKDRAFT SLAVE/MASTER CYLINDER cont.. Still having issues

[madmaxx]

I agree, but based on his off the shelf parts, tko 500, ford racing engine, i do not see anything exotic that would require anything but stock.

Originally Posted by Rick Parker

There are MANY variables on the clutch that could affect necessary changes in Master and Slave sizing ratios too.

[vector1]

since it is heat related i would guess your fluid is getting hot somewhere and boiling, either in the lines, slave cyl, or master cyl.

moisture in the fluid lowers boiling point also.

get a temp gun and check your stuff after you've run it.

[Jimbocobra]

Bill was terrific as are all of you with your suggestions. My local mechanic at Komet Motorsports has seen a few Cobras but is always willing to learn - a sign of a bright guy. I ordered a new master along with Bill's bracket and slave. I have about 10 miles on the Wildwood pull (anyone want it?).

My car was originally from Florida (Reg Dodd). If anyone knows what type of fork they use, please feel free to chime in.

We will find out if it works as soon as the parts come in and I get them installed. To be continued... I will share the results with the forum.

Thanks to all

[mikeforte]

Hi Jim,
I make many external slave systems for different bellhousings. I have almost exclusively gone to push slaves because of reliabilty issues. I'm sure I have a kit that'll work with your combo...
What engine do you have?

[Jimbocobra]

I appreciate it, but I already placed the order from Bill Littleton. If it doesn't work, you will be my next call. I have a Ford crate 392 and I guess a standard bellhousing.
Thanks,
Jim

[mikeforte]

Hi Jim,
I have a simple bolt on slave fork assembly for the TKO aluminum bellhousing.
Why it fails when hot could be several reasons. To much heat on the master cylinder or hydraulic hose, failing slave or master. Any leaks?
I would need to inspect everything to determine the actual cause but it must be obvious

[Jimbocobra]

Mike,
After speaking with several people, I believe that the master might have some internal wear, possibly caused at some point by the lack of heat shield coverage. The first time I changed the fluid at 2000 miles it was burnt and nasty. I was told that it turns acidic and could have corroded the "o" rings and caused a lack of pressure. That might have explained why in the past when it got really hot, I would sit a light and the car would slowly start to move forward even when I was standing on the clutch.

After all the work I had done on it, the problems are less noticable, but it was still starting to get hard to get into first.

I think that when the car got hot it burned the fluid causing the slave to go first, but still did less noticable damage to the master. I have moved and coated the lines, change to a DOT 4, non silicone, high temp fluid, changed the slave. Now I will swap out the master, try Bill's new set-up. As everyone said, I have a standard Ford 392 crate motor, TKO 500, traditional bell housing. Basically, I will have replaced almost the whole system;
New lines, new fluids, new slave, new master, moved and coated the lines...
If this doesn't work, maybe I'll buy an new ZR1 with a warranty. Naaa! The Cobra just looks too good.

[vector1]

if that pic is yours, the oil going through the filter is prob 250+ on a good day, you might want to shield the master/slave cylinder.

[Jimbocobra]

I think the pics are Mike's. I have my master completely covered with custom made heat shields. Thanks, Jim

[madmaxx]

I drove my spf 80 plus miles, put it up on the 4 post and my slave was cold to the touch. For brake fluid to boil you have to be at 401F, rest assured noyone is getting that hot. Talk to bill about the silicone, you should have never put that stuff in, i assume you can flush your clutch master cylinder with no ill effects. Silicone is designed for classic cars which get driven very very rarely. Google it, since water does not emulsify in it it readily boils, however it is good for paint since it does not deterioate it. Just use the run of the mill preston dot 4.

[tony martin]

Jim,

here is something simple to look at and try.
Depress your clutch pedal completly.
If it bottoms out on the fire wall adjust the rod on the master cyl out wards until the plunger stops the pedal.
Then adj it back just a tad,so it does not strain the cyl.

I say this because some bdr,s built around this vin.no had a master cyl with a slightly shorter stroke.
On these few cars this adjustment was critical.

Let us know if this helps.

regards

[Mac VABCH]

Hydraulic throw out bearing.......

[Gatorac]

Ok, every clutch slave issue thread I post the same thing. I'll post it here for future reference. You must bleed the clutch system out every 6 to 9 months. Period. Do it. My first MC and slave failed 1 year after 181 was on the road. I replaced both the MC and slave with the same parts it came with. I have bled it out every 6-9 months since and I have not had another issue since. 181 has 11k miles on it and is 4.5 years old.

The brake fluid gets cooked. When it's in that condition, it will eat the seals in the MC and slave. Jim, the symptoms you describe tell me the MC has failed to. Replace both the MC and slave. Use a good DOT 3 or 4 fluid and bleed often. You won't have another problem. A hydraulic throw bearing is not needed and a PITA to install or replace. I you don't maintain the fluid the hydraulic throw out bearing will fail too.

The proper bleeding procedure is in several of the many threads on the subject in this forum.

This is all my personal experience with BDR 181 that I have owned and serviced for 4.5 years myself. Those with no experience may have different opinions that you can choose to listen to if you like.

[Tangible Toys]

Hey if nothing is leaking Jim is right, but the units are "cleanable" with Brake clean and reassembled with ATE blue fluid, and flushed with it too. If you want to cut corners you can bleed it with "blue" and you can buy "time"

[Jimbocobra]

We swapped to Bill Littleton's set up. The slave set up is better than the original design. We replaced the master, but I think we need a bigger MC because it does not seem to work with the new larger slave. We are calling Wildwood tomorrow. Unfortunately - still to be continued.

[Cashburn]

Jim,
Listen to Tony. You have a build number where some experimenting went on with the Master Cylinders. Bill's setup will require the proper master.

[Blittleton]

Jimbo,

The Master cylinder and the slave cylinder are a match, adjust your pedal properly. I would hope your mechanic can adjust your clutch properly as well.

Bill

[Jimbocobra]

Bill - sounds like it might be the wrong slave?

[rocket7171]

Out for 1st day today.
I went to Bill's set-up and it worked fine until hot. Then grinding only in reverse when hot. When the car is cold there is no problem. I do have coated headers but no heat shields. Should I look at stroke and try to adjust? Only when hot.
tom

[Jimbocobra]

You can try adjusting and assuming no real damage has been done, you might get away with it.

The parts are pretty cheap, it is either the slave, master or fluid. Just replace them all. If you fried the fluid and have not done damage to the slave or master the adjusting the clutch won't fix it.

Knowing what I know now, I'd would have moved the lines, installed the new version of the heat shields, wrapped the lines, installed Bill's new slave and a larger new master cylinder all at once. Doing it one at a time was a waste. I knew I had to change the fluid, it was pretty dark, but I did not realize that it could cause the slave to leak or the the "o" rings in the master to internally leak.

Basically, you may fix one issue and not realize that one or more of the other issues might have already begun. You fix one, it works for a while, but the other eventually fades. All the parts combined were less that $200 and it beats chasing your tail, trying to figure out what went wrong.

Good luck.