Slave cylinder fails.

[clinck]

I went to the local Saturday nite cruise-in in Scottsdale last night. I puuled into a parking space and shut her down to relax with a few friends for a couple of hours. At 9PM I decided to head back the 35 miles north to the ranch. I got in the car and pushed the clutch pedal to the floor with no effort. The clutch was AWOL...gone. After inspection I discovered a puddle of fluid directly under the slave.
Well, I got a tow truck ride home last night and a $113.00 tow bill. Not exactly what I was going for but in the end I was happy to get RUBY home safe. Towing with flat beds is always damage control waiting to happen.
Now the question is to my friends here is how difficult is the exchange and do I call the weaver's on Tuesday to get the correct parts?
What would cause that slave to fail. The car has about 1250 miles since Jewff Karnitz finished the build in 2002. That seems like an extraordinarily short life for a part to me. Some of the guys out here say that that's a recurring problem with Cobra's. I don't know.

Thanks for the help!


Sundown

[dmiller]

i recently had my wilwood slave cyl fail, this is "pulling" the clutch release arm forward to release the clutch on a mustang style bell housing. i think that the cause of failure was the proximity of the slave to the main exhaust headers on the driver's side. the low pressure side of the cyl had fluid in it, and was preventing the piston from pulling forward as it compressed.

i put a new cyl on and 1) made a heat baffle that attached to the main frame and shields the cyl from the radiation heat off the headers, 2) wrapped the fluid lines with insulation.

so far, about 600 miles since repair, no problems.

if i remember the more typical arrangement on the weaver endorsed bell housings, your cyl pushes the clutch arm toward the rear of the car to release. in that case the cyl is not as near the header as is my cyl.

nothing more depressing than a "ride" home in a tow truck.

good luck,

doug

[pgermond]

I don't know why yours failed, but some preventative measure can't hurt. I wrapped my slave with the same heat reflective material I used on the starter. Also used heat reflective sleeves from Cool It on the hydraulic lines.

Sure seems to be a lot of clutch issues on the forum :( Must be 'cause everyone is driving :D

Phil

427 Roadster, #4279436
Southern Automotive FE
3:31 and Toploader

Roseville (N.Cal)

[clayfoushee]

Chris, depending upon which type set-up you have, it's not very hard or time-consuming to replace, and you should be able to find one locally. I agree that that foil-lined insulaton is a must do mod, that saves both brake and clutch components. On most cars, all that stuff is too close to the headers.

Clay

'98 Unique #9299, 427FE side oiler, top-loader (close), 3.31 rear

Annapolis, MD

[Poorboy]

Chris,
If you have the one that bolts to a bracket on the block at the bell housing the part is a EIS #EW33721. Any good parts store should be able to change that # over to their brand or any other.
Check the alinement of the push rod with the clutch fork. It should push stright not off to one side of the slave.

Poorboy

[gasman]

Sundown, you probably do not need a new part. I'm sure the cylinder needs a simple rebuild with a new O ring and fresh fluid. The smartest modification I saw at Homcoming were the cars that ran the master cylinder lines over the foot box and down the side of the bell housing which is at least a foot away from header heat. Keep the fluid cool and the parts stay cool. I also think an insulation box under the master cylinders is a must modification. Insulating the lines that are close to headers will prolong the fluid life but the best long term fix is get the lines away from any heat source.

Steve Foushee
Unique #4279389

[brfutbrian]

chris, like poorboy says, if its the one unique uses, you can get a replacement almost anywhere. it probably isnt more than twenty bucks. and before you trash the slave cyl make sure the line didnt come loose and caused the leak. later, brian

[Silk]

Chris,

As said above, this is an easy replacement. Here are a couple of part #s for the standard slave cylinder: Wagner F 124-111 or Raybestos #SC-33721. I found that the Wagner was the easiest to source.

Gary
Unique FIA 351W

[rdorman]

I don't know which set up you have but my wilwood seems to go about once a year. I keep a spare one and rebuild them as I go.
Rick

[dmiller]

rdorman:

does the wilwood give you any warning before failing? or just fail without any warning?

i'm using wilwood, had one failure early on, 200 miles, and now have 700 miles on replacement, and all seems ok.

thanks.

doug

[clayfoushee]

Doug,

I have almost 2K on mine now, but I have all the lines well insulated. I've seen a number go on other's cars in the last year, and they always seem to just fail. One minute you have clutch the next you don't. I think the heat from the sidepipes tends to kill the hard rubber seals and they essentially give out and start leaking. It's certainly not a scientific sample, but those who have re-routed the lines, or insulated well seem to rarely have problems.

Clay

'98 Unique #9299, 427FE side oiler, top-loader (close), 3.31 rear

Annapolis, MD

[dmiller]

thanks, my failure was immediate with no warning,

i now have heat protections, hope that is the answer.

thanks

doug

[rdorman]

Mine went without warning. I keep my spare in the trunk as it is easy to change out.
Rick

[eliminator]

STRANGE[?]
Havn't heard anyone on here talking about their Hyd. Throw-out Bearing failures[:O]
According to most of the experts they should be in the garbage can anway;)
You guy's with clutch problems need to look at a more permanent fix.
If you can build a car, you can install a HYD. Throw-out Bearing.[^]

Rick
#4279405

[Silk]

Rick,

That's fine, except for those of us who have had our real problem with clutch master cylinders! :( I'm on #4, with a spare in the trunk. Makes me wonder about the benefits of reverting back to clutch cables. [8D] And for those of you who are more enlightened in this area, can you explain why clutch cables aren't superior hydraulics?

Gary
Unique FIA 351W

[dmiller]

i'd vote for cables!

that's the FORD designed it to begin with, at least on mustangs.

doug

[eliminator]

You know I have heard about alot of Master Cylinder failures lately.....what gives.
May just buy an extra one for stock..
I am sure Wilwood can do better than that.

Rick
#4279405

[Silk]

Not quite sure why mine were cratering - I tried insulating the line to the slave, racing fluid, etc - but I think the problem was the piston bottoming in the cylinder and destroying the seal over time. On my last install, I measured & marked the rod when fully depressed, then made sure that when installed, it was backed off about 1/4 inch from bottom when the clutch pedal is fully depressed. That was some 3000 miles ago and all seems well. Sure hope so, because it always seems to fail in hot weather, giving me the fabulous opportunity to crawl around upside down in the footwell bathed in sweat! :( :D

Gary
Unique FIA 351W

[Poorboy]

Doug;
You come up the pedal assembley,cables,pullies,adjuster, etc. and they might think about using it. These are not Mustangs.

[dmiller]

poorboy, not trying to offend anyone, certainly not the Unique design team.

but with a clean sheet design, the cable system might have some advantages. i know that my system's failure was my fault for not protecting from exhuast heat, (i hope that was the problem). but there appear to be many system failures here. surely some of the blame is hydraulic, and other is that there are so many different choices of engines, bell housing, clutches, etc. if there was only one approved engine drive train offered, then the design would be more proven, and reliable.

i am not a knowledgable auto mechanic. prior to this, only experiecne was trying to keep an old TR-3 running. it too had hydraulic clutch system. until i crawled under a mustang to get an idea of how the clutch was supposed to be plumbed, i didn't know it was cable.

once again, no offense was meant.

doug

[clinck]

Wow, I guess I touched on a sore spot we all know or will know. There is an immediate failure of this part. No warning. Just dead. Thank goodness I was parked at a car show on a sleepy Saturday night. I called my faithful towing service [we're on a first name basis] and he took me the 35 miles home. $113.00... thank you for your business.
Am I being to critical when I think that the Allan and the family know that these slaves fail and continue to buuld them into the car in highly suspect conditions.
For me, this little wilwood part [rebulid kit] #260-5524 @ $13.95 will end up costing a bunch more.
There isn't such a beast in stock in town so my car is tucked into a car ocver in the garage waiting for me to find the correct parts. It's 110 degrees today in Phoenix so I wasn't planning a leisure cruise anyway.

I don't have a car lift so if I want to safely lift the car to make this repair what are the best options for safety and convenience.
Should I jack stand all four wheels?

Good answers anybody?

Thanks

Sundown

[pgermond]

Floor jack on the center of the x-rails, front and rear. Four jack stands (inside rails - front & rear).

I slide the floor jack in between the front of the rear wheel and the side pipe for the rear. In front, between the front of the front tire and the oil cooler.

Phil

427 Roadster, #4279436
Southern Automotive FE
3:31 and Toploader

Roseville (N.Cal)

[Silk]

quote:Originally posted by clinck

Am I being to critical when I think that the Allan and the family know that these slaves fail and continue to buuld them into the car in highly suspect conditions.

Despite the issues that many have had with master or slave cylinders, I think the components themselves are fine - it's just the instillation that can be problematic. While I've gone through a number of master cylinders, I'm pretty certain I've figured out what the past problem was (not the fault of the part) and corrected my instillation accordingly. As you read through threads on various Cobra forums, you see very similar issues arise in a number of other areas - vaporizing distributor gears comes to mind. Again, nothing wrong with the gears, just proper instillation/compatibility issues. These are, after all, component cars that are not put together on the assembly lines of major automotive manufacturers. To me, it's just part of the experience of owning a Cobra. And a good opportunity to learn a few things as I go along. :D

Gary
Unique FIA 351W

[spd4me]

The best way to jet car up on stands is to slide the jack under the cross member just behind the radiator. I put a 2x4 12" long with a piece of carpet between jack and member. Jack both front wheels up at same time. Put jack stands with carpet on top under "A" arms as close to wheel without interfering with grease plug. For rear, I put jack with 2x4 under middle of jack plate under differential. Jack both rear up at once and put stands under lower arms at hubs. Weavers told me not to jack car from side.

[Poorboy]

The plate under the differential is not a jack plate ! With the 2x4 you might be all right but with out it you probability bend it. On the front with the 2x4 and carpet you take a chance of it slipping off the jack. If it slips off the back it's not to bad, off the front the radiator will keep it from hitting the floor.

[clinck]

I talked to alan yesterday regarding the slave failure and he gave me the correct part number. I went to Napa and bought the correct piece off the shelf for $49 pesos. Alan advised that the problem was caused more by inactivity than the heat and that fact that I brought the car to sunny, no humidity Arizona.

My problems are essentially over. I still must figure out how to get the car off the ground. I need to buy jack stands or a lift. I want the lift and can afford the jack stands. Going to buy jack stands tomorrow
I talked to my home builder yesterday too. I told him to come by and give me an estimate for heat/air conditioning for my garage. I'm tired of not having the use of my own space because it's a 110 degrees outside and over a hundred in the garage. THEN, I will buy the lift and go at it full steam.


Sundown

[rdorman]

I drive the front up on ramps and then jack the rear on the frame just inside the body work under the trunk. Place stands on the four corners. Quick and easy.
Rick

[spd4me]

Poorboy
Your right, there's nothing worst than a car falling on your head. Ouch! I use one of those roll around jacks so when it goes up, as the car moves the jack rolls alittle. I immediately put stands under the frame in front of radiator just to catch the car if jack fails. In a Jaguar manual I've got, they refer to the rear plate under the differential as a "jack plate". Maybe the jacks they used were made to fit the plate?

[ralphscott]

One of the Cobra guys up here Knoxville designed a plate to bolt under your differential so you can jack the car up. It is pretty straight forward with it bolting into the differential frame and a hole in it for draining. Dan Fowler is his name #22 the white Cobra. When I jack up my Lil'Cobra I use a hydraulic centered under the front cross member and place the stands under the front frame corners. Place a wood block rest with stops under each front wheel (made to fit the car when on jack stands to resist rolling) then I jack up the rear using the differential plate and put the rear stands in the frame corners and place wood block rests with stops under the rear wheels. Car is stable. Reverse the procedure to take it down. Takes a little longe 'cause you need to fabricate the blocks I really don't trust hydraulics. Reference the slave clutch thread.

Ralph