Backdraft Slave Cylinder - part 3 -

[Jimbocobra]

Well, pretty much tried everything - even Bill Littleton's new parts and it still doesn't work properly. I have had a couple mechanics look at it so it is not the installation
I have tried:

3 Slave cylinders
1 new master
wrapped the lines with heat protected coating
added head shields
replaced the fluids twice
used Bill Littleton's new set bracket and slave

There has got to be a better way, this $60 part has cost me over $1,000 in repair bills. Surely I can be alone, anyone out there still having problems with the BDR setup? What is the deal Backdraft? This seems to be a common problem. Do you have a solution, or do I have to break down and buy a Superformance instead?

[PLDRIVE]

Hi Jimbocobra,
Could U give us a little more info? since you have added the heat shields how many miles before slave (or slaves) went bad? Was the fluid black? What fluid are U using? R the Lines away from the Headers? I have had no trouble with my
Slave (CNC slave) or master (I have 2200 miles on car). i have changed the fluid once.

[Speedysnake]

Check my gallery for a pic of the mod I made to the original design (wilwood) slave cyl. mount. It's been in place now for about 6K miles, no problems.

[Rwillia4]

Are you using a push or pull setup? I installed a pull setup and really like it. I'll take some pictures if you are interested.

[Gatorac]

I had a problem the first year I had the car. Replaced master and slave. Since then I change fluid twice a year and I haven't had another problem. It's only been five years though. It's the stock BDR setup.

How about some details on the issue you're having.

[dlampe]

Is there a way to post part one and two at the beginning of the thread? What is the problem you are facing? Is it a bracket problem, not enough movement at the clutch arm, no fluid coming through, won't engage the clutch or some thing different? These guys on this forum are the sharpest I have ever met. Lay out to specific problem and I'm sure it will get fixed. For me, my next BDR will have a hydraulic bearing.

[andronikos916]

Hello,

I also have the same problems with the slave cylinder. My car is a BDR#755 with 1200miles.

I had to change twice the slave cylinder. I bought the car with 670miles used and after 50miles slave died. At that time I thought that it was previous owner's fault that never bleed the fluids. So I used again the pull style willwood slave and after 500miles - with brand new fluids (Dot 4 Motul RBF 600) the slave started performing weird. I discovered that the the shaft inside the cylinder in the slave come loose. So, I opened it and locktite the shaft.

Now it is not perfect but needs to push the pedal 2-3times to have a good feeling. Also difficult to put Reverse. I believe that the O-rings needs to be replaced.

Anybody knows the replacement kit for the following slave?

Here is a pic from the willwood Slave cylinder 260-1333.


Since I still have problems I will also order the bracket from BDR and give a try the Push Style slave setup.


Hope this push slave will work better. Anybody with a permanent solution?

Andronikos,

[andronikos916]

I think I found the replacement Kit. Is it this one?
Wilwood Disc Brakes 260-5524 - Wilwood Clutch Slave Cylinder Rebuild Kits - Overview - SummitRacing.com

Best - Andro,

[Rick Parker]

If you can redesign the installation so there are heim joints on EACH end you will go a long way in eliminating what ever issues you are having. These things MUST pull in a straight line to work correctly, if they do not, the piston inside is pushed to one side as it travels, it will quickly wear a pattern that will cause an internal leak. You will recognize this being the case, since the symptoms are the required pumping of the pedal to gain proper travel of the release lever and clutch. If a strengthened clutch pressure plate is added due to increased HP the wear problem is increased. Think STRAIGHT LINES. Sometimes those we take the car to for repair are only changing parts, and don't realize some re-engineering may be required. This is Hydraulics 101 applied to an automotive application.

[andronikos916]

Yes I agree with you Rick. I have done that. At least I tried, it looks strait - but I am sure it is not, since I opened the slave cylinder and I saw some wear inside.
I will try to take some pics to show you what I have done.
Maybe instead of making things better - I am creating more angle...

But since the clutch pedal is moving, it is changing the angle a bit. I gave a small tolerance as well.

Best - Andro,

[got snake?]

Jimbo!!! Sorry hear about the slave issue again.

My cobra was working GREAT with it's new hydraulic throwout bearing. Then it desided to relieve itself of fluid. Getting it fixed again. But it did work for an entire year without any issues. Didn't drive it much though so not sure how many miles.

[Rick Parker]

The later style (OEM cable activated) clutch arm (pivot on internal RH side of Bell Housing) swings in a larger (arc) and (longer) travel than the early mechanically activated type. Adapting the hydraulic sysyem requires removing as much potential side to side binding as possible for long slave cylinder life. If you can incorporate a rod end into the release arm it will go a long way to extending the longevity. Look in the Book "Prepare to Win" By Carroll Smith for examples of how to do it.

[GLS-BDR226]

I had to replace the push slave after about 1800 miles. The previous owner never bled and flushed the slave. I installed the slave from BDR and the heat shield under the master. I haven't had a problem and now have about 6300 miles on it. I have flush it once a season. It is an early BDR so I used heatshield wrap around the line to the slave.

[elmariachi]

Regardless of which slave you use and how it's set up, make sure you don't use any rubber lines. The best setup is a hard line from the master and a flexible braided stub line in the last few inches to permit flex between the body and driveline. A rubber line will expand under heat from the exhaust and reduce line pressure, resulting in a soft or no pedal.

[Jimbocobra]

[quote=got snake?;1153898]Jimbo!!! Sorry hear about the slave issue again QUOTE]

Sid - that post is from 2009, My car has been fine for the last 2 years (if you don't count the other things I have fixed like a leaky differential, transmission upgrade from bent shift rods, cracked side pipe that had to be welded, seized knock off, loose half shaft bolts, loose tach, front end alignment, blown fuses, broken trunk latch, loose valve covers, new tires front and rear, broken front wing window, loose spring on the LeMans gas cap, broken baffle in side pipe etc...) typical maintenance stuff, particularly when you race the car. Better said, my slave cylinder has been fine for two years!

[jhv48]

I too have been having a battle with my clutch.

After many man hours and $$$$ spent chasing the problem, it finally boiled down (literally) to a heat problem and the push rod from the slave not pushing in a straight line. Once the push rod was straightened (a new slave mounting bracket was fabricated) then I had to deal with the heat problem. The car shifted beautifully when cold, or while moving. When stuck in traffic in the summer temps, it would become impossible to find reverse without grinding and puting into first at a stop became very difficult.
I had to fab some heat shields for the clutch lines and switched to wilwood high temp brake fluid. I also found that bleeding the system every 6 months helped eliminate the problem.

So, my recommendations are:
1. Make sure push/pull rod on slave cylinder is moving in a straight line.
2. Use heat shields as much as possible to shield the lines from engine heat.
3. Use wilwood high temp fluid (boiling point around 570 degrees whereas normal fluid is in the 300's).
4. Bleed the system twice a year.

Took me two years of trial and error and $$$$ to fix mine. Hope this works for you.

[Trueoo7]

While I haven't heard it mentioned much, don't overlook the fact that the pedal pushrod into the master cylinder should be adjusted correctly. Before I changed out my slave and eventually master cylinder, my clutch didn't always feel right either. Sometimes had to double pump, reverse was sometimes a grind if I didn't stop the synchros first by putting it in second. When I finally changed the master out, and didn't get much of a change, if not a little worse, I looked at the adjustment of the pedal rod. A few turns out resulting in a longer stroke with more throw and its a whole different car now (makes me wonder if I even needed to change out the cylinders). No grinds, smooth as silk, a pleasure to drive, no more reverse problems. What a difference a few turns can make.
Probably about 1000 miles since the adjustment and still as smooth as the day I did it.

[Trueoo7]

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