Clutch Slave Cylinder change?

[mkassab]

I've heard of issues with the clutch slave cylinders on our Cobras, e.g., leaking, wearing out prematurely, breaking. My car only has a few hundred miles on it and already the slave cylinder has drops of brake fluid. Heck, while at the Emerald Coast auto show, one of our fellow Cobra owners had his slave cylinder go out at the Cruizin the Coast (MS) show last Oct. He's going with a cable set up. Not being one to wait and have a failure out on the road, I'm changing to something different. I'm looking to this forum for ideas, pictures and suggestions. I'm currently looking at the Wilwood slave cylinder. It only comes in a "pull" and the standard Unique setup on our 427s is a push. The pull isn't a show stopper, I'd just need to make a bracket. This will be a good winter project. I was going to bleed the brakes and clutch anyway. :o

I'll keep you posted with my modification.

Thanks Mark

[Jim Harding]

Mark, most of the failures I've seen are due to a misalignment of the slave cylinder. The misalignment is noticeable when the slave push rod does not exit the slave exactly perpendicular, i.e. a slight angle between the body of the slave and the push rod. This causes abnormal wear on one side of the piston/cylinder rather than even wear around its circumference. Careful realignment of the slave will cure your problem.
The Wilwood pull cylinder will do the same thing if there is misalignment. I'm using a Wilwood pull slave on my black car and it has been trouble free since it's installation back in 2000. So far, the push type on my silver car has gone over 3K without a problem..... oh oh, maybe I just jinxed myself:rolleyes:

[mkassab]

Thanks Jim..... I've read all the past threads and mind is misaligned also. The good thing about the Wilwood, it has two swivel/pivot bearings, one on each end for a 360 deg of movement, and if mounted correctly, the slave cylinder is always in a straight line, therefore, no side pressure. And, because its pulling, vs. pushing, it’s easy to keep itself in a straight line (like pulling a rope vs pushing one). I'm designing a bracket know and plan to weld up over the weekend unless someone has a better design/idea.
Picture attached
Mark

[davebetts]

Alignment is key, but don't forget to use the Wilwood High Temp brake fluid. Not doing so has caused failures in itself - fluid cooks from overheating and Game Over. Also, I remember guys putting the updated Dot 5 and/or synthetic fluids in - again failure from heat and/or rubber deteriation. I belive regular Dot 4 is the correct fluid. Hope this helps.

[mkassab]

Thanks Dave.... regarding brake fluid, I use Amsoil DOT 4 racing brake fluid, rated for 600 degs

Mark

[spd4me]

Mark - I changed mine from the Lockhead push to the Wilwood pull. I've got some pics I'll find and send. I made a U shape bracket of 1/2" steel to weld to frame to attach slave to. I found a 3/4" ball bearing and had it cut in half, drilled hole and used to attach slave to clutch arm (half ball fits in indentation in clutch arm). Works perfect and had no problems.
Bob

[spd4me]

Here's a link to forum photos
http://www.uniquecobra.com/forums/showthread.php?t=6097&highlight=wilwood+slave

[weaver]

Did the Wilwood slave make for a harder pedal?

[mkassab]

Mark - I changed mine from the Lockhead push to the Wilwood pull. I've got some pics I'll find and send. I made a U shape bracket of 1/2" steel to weld to frame to attach slave to. I found a 3/4" ball bearing and had it cut in half, drilled hole and used to attach slave to clutch arm (half ball fits in indentation in clutch arm). Works perfect and had no problems.
Bob

Thanks Bob.... I'm pretty much doing the same thing. When you bleed the slave, do you just rotate the cylinder bleed valve to the 12 oclock position?
Marj

[Justin Upchurch]

I recently switched from the McLeod Concentric (Leaking POS) to the Forte setup. Although I think Forte's CNC slave and bracket are over priced, it does look good and work.

Justin

[mkassab]

Hi Justin.... I was looking at Forte's set up. Does look good, but I've read a lot of issues, of late, with it on various forums. It also appears it doesn't swivel on both ends like the Wilwood does? If it doesn't, side load will end up being an issue. Another good thing with the Wilwood, a rebuild kit is avail.

Mark

[spd4me]

The pedal movement is smooth as glass. Just as easy or easier than the push style Lockheed. Just rotate bleed valve to 12 oclock and start pumping. The major problem I had was the clutch arm hitting the inside of the bellhousing and not traveling enough to disengage the clutch. Fixed that with a 1/2" spacer.
Bob

[spd4me]

One other thing to look at is the amount of travel. The wilwood gives the most travel of all I researched. 1.25" if I remember correct.

[mkassab]

One other thing to look at is the amount of travel. The wilwood gives the most travel of all I researched. 1.25" if I remember correct.


1.38" to be exact. I measured the original travel at the end of the arm while my wife depressed the clutch pedal all the way..... it was only about 1/2 inch. So the Wilwood has that covered with no problem.

Mark

[spd4me]

Mark - All I got before was 1/2" travel and it wasn't enough to disengauge clutch (esp. when putting into reverse). Problem was clutch arm was binding on bellhousing. See attached photos. Solved by replacing 2 washers with a block of 1/2" steel with 2 holes drilled.

[mkassab]

Mark - All I got before was 1/2" travel and it wasn't enough to disengauge clutch (esp. when putting into reverse). Problem was clutch arm was binding on bellhousing. See attached photos. Solved by replacing 2 washers with a block of 1/2" steel with 2 holes drilled.

What attached photos?

[spd4me]

trying to attach photos

[mkassab]

The new Wilwood slave cylinder installed with the bracket I fabricated. The only thing left is to connect the line and add/bleed brake fluid.

Mark

[Justin Upchurch]

The Forte Unit came out straight, but to get it the way I wanted it, I had to put in a longer actuator rod. I went up to a 7/8 master and the pedal is still much lighter than the McLeod. Bonus is if it leaks, I don't have to drop the trans again.

Make sure to check your solid-roller lifters every couple of thousand miles. My $800 Isky Redzones just spit the bearings out.

Justin

[mkassab]

Make sure to check your solid-roller lifters every couple of thousand miles. My $800 Isky Redzones just spit the bearings out.

Justin

I only have 318 miles on the engine, but I pulled the valve covers, popped out the spark plugs and adjusted all the valve lashes. While doing that, I also installed a new timing mark and tape at the 11:00 position…. Much easier to see. I first had to cut off a senor mounting piece on the water pump housing (used on later model Fords) to alow the new Ford Racing timiming mark to flush mount. The harmonic balancer I bought had the TDC at the 1:00 position which was absolutely impossible to see. This new one is perfect. I also pulled the front hubs/calipers and installed saftey wire in all the rotor to hub bolts and caliper to mounting bracket bolts. Winter projects, got to love them! :banana:

Mark

[diegokid]

Will the slave cylinder have enough travel with the cyl. attached all the way out on the end of the actuator like that? It should be easier to operate but won't it lose travel?

[mkassab]

Yes, the picture doesn't show all the clearance. The cylinder body will move rearward and has lots of clearance. Any future adjustments will be made from the clutch arm end. This is a Pull slave cylinder, so it should be all the way out.
Mark

[mkassab]

diegokid sent me a PM with a good question. I wanted to share Q&A with everyone.

Originally Posted by diegokid
I think you may have misunderstood. The pivot arm that actually disengages the clutch through the bellhousing has a divit in it for a rod to push on. The divot keeps it from slipping out.

I was just wandering why you didn't hook the slave through a hold drilled there instead of out on the end of the arm? That will give you less travel on the throwout bearing that if it was drilled to the divot.
I was going to use the divot area and drill a hole, but my clutch arm must be harden steel and my drill bits wouldn't touch it! The hole I used is only ~3/4" out from the divot and the pivot angle in a few deg's and distance of travel is only ~1/2” so it shouldn’t be an issue. One benefit using the outer hole is a little more leverage.

Mark
__________________

[spd4me]

Mark - Just be sure the slave arm where it attaches to clutch arm has slack enough to move and not bind. That's why I drilled mine at the dimple and used the curved bushing. Left some slack and tightened on the opposite side of clutch arm. I'll get a photo tonight and post tomorrow.

[spd4me]

It's tomorrow already. If you look close yu can see the ball bearing I cut in half to fit in the clutch arm dimple. Lock the nuts together and it has room to slide in the dimple.

[mkassab]

I'm good to go with the stud through the clutch arm hole relative to free motion. I also "rounded" out the far side of the clutch arm hole where the half-round bushing pivots with a round/ball type grinding wheel via my air grinder... then applied a small amount of wheel bearing grease. And to keep the cylinder from moving back and forth, I reversed it. See new pictures.

Mark

[diegokid]

Some call them rotary files, we call them burr bits. They will drill/cut through just about anything you will find on our cars if anyone else is interested. I used one to burr a hole for a return spring on mine. Many different shapes and sizes.

[spd4me]

I've got a set of carbite for steel and non-ferris for alum. Use to port my intake and exhaust manifolds and to cut centers out of alum spinners on wheels. Need a real strong air compressor to operate when using the "wheel of death" air tool.
bob