BDR slave cylinder failure - Page 2

jp65cobra · #21 (**permalink**) 07-29-2008, 11:57 AM

Al,

I would say yes to bleeding the brakes as well. I have seen several posts about this over the last few years and read about some guys getting to the track for a day of fun but having to work on their brakes. I do both brakes and clutch at the same time.

Regards,

John

JayBar · #22 (**permalink**) 08-07-2008, 01:07 PM

Here is my slave setup with the Termic TKO 600 with a McLeod steel pressure plate. The setup is not my design but one Reg and David came up with. The only thing needed beside the "puller" slave is a brass bushing to insert in the hole normally reserved for the clutch cable, it cars so equipped. I went through several brand name slaves. Seems the rod was screwed into the piston, and this would come undone. Yes even with lock tite, it came apart.
I bought a slave from www.speedwaymotors.com much cheaper and the rod is "peened" to the piston so it can't come out.

Gatorac · #23 (**permalink**) 08-07-2008, 02:28 PM

Please remember that the brake and clutch use different fluids in the BDR (at least most do). They are not compatible. The brakes use the DOT 5 (synthetic) fluid. It does not absorb moisture. If you don't bleed the brakes the moisture will accumulate in the calipers and cause problems.

JayBar · #24 (**permalink**) 08-07-2008, 03:49 PM

Jim,
You are correct about the BDR fluid. I researched it and found no good reason to use DOT 5 other than it is easier on your paint.

In speaking to guys that track BMW's they tell me they use a good DOT 3

So I bought a quart of cheap DOT 3 and flushed my brake system then added ATE Blue. So now I have one fluid in both systems.

Jimbocobra · #25 (**permalink**) 09-25-2008, 06:41 PM

I have been reading these forums and this sounds like some people have the same issue as I do. Basically, when the car gets hot I have to wrestle with the gearshift to get it in gear, it grinds when I put it in reverse. It is getting to the point where there were several times I literally could not get the gear shift into any gear. I don't beat on the car; it is a Backdraft and has less than 3000 miles. To all of you who know about this stuff, do you think it is the slave cylinder overheating? If so, is there a consensus on how to fix it. I have heard to replace it with a hydraulic set up, use a heat shield, change the fluids and use heat resistant tape? I am sure I can't fix something like this. #1 What do you all think is the issue? and #2 any know a good speed shop around St. Charles, IL who knows how to fix this?

Gatorac · #26 (**permalink**) 09-25-2008, 06:52 PM

How long have you had the car? Have you bleed the clutch system yet?

It may be to late to bleed and you may have to replace the slave and master cylinders. Bleed every 6 months. Hey, I think I've heard that somewhere before......

JayBar · #27 (**permalink**) 09-25-2008, 07:07 PM

Jimbocobra,
You don't need a speed shop you can get all the info you need on this forum, form people who have been there and done that. You have a hydraulic set up you just have to keep the fluid from boiling. You only need a few tools nothing special set of
open end/box end wrenches.
Your problem is simple, buy a heat shield from Backdraft, change the fluid to one that has a high wet boiling point. I use ATE Blue maybe about $12.00 to 18.00 a can. Suck out the fluid from the clutch master, refill with good quality fluid, open the bleed screw on the slave and pump the fluid through.

Rick Parker · #28 (**permalink**) 09-25-2008, 08:18 PM

Does (BDR) use the rubber hose as shown in the photo or is it left to the builder to utilize what they want? The heat may be breaking down the rubber cup within the slave and/or the internals of the rubber hose.
I had used at one time the same exact slave (pull type) and it was mounted away from heat and it worked well for over 6 years, and never leaked.
You might reconsider the mounting location and install it behind the lever and use a "Push type" slave, then it would be away from heat in your case.

Blittleton · #29 (**permalink**) 09-25-2008, 08:23 PM

Quote:

Originally Posted by Jimbocobra

I have been reading these forums and this sounds like some people have the same issue as I do. Basically, when the car gets hot I have to wrestle with the gearshift to get it in gear, it grinds when I put it in reverse. It is getting to the point where there were several times I literally could not get the gear shift into any gear. I don't beat on the car; it is a Backdraft and has less than 3000 miles. To all of you who know about this stuff, do you think it is the slave cylinder overheating? If so, is there a consensus on how to fix it. I have heard to replace it with a hydraulic set up, use a heat shield, change the fluids and use heat resistant tape? I am sure I can't fix something like this. #1 What do you all think is the issue? and #2 any know a good speed shop around St. Charles, IL who knows how to fix this?

Jimbo,

I'm just south of you in Hebron Ky. I can fix your problem. Give me a call and I can help you with the setups I use. I use either a hyd throwout bearing or a slave cylinder depending on your needs. Other dealers seem to use the same ol design or inferior slave design.

Bill
859-630-9099

JUS BIT · #30 (**permalink**) 09-25-2008, 09:08 PM

I've been installing the Wilwood Pull Slave down here on the cars that we've built. No problems on our cars at all. Also, with an external slave, it's a lot easier to replace if failure occurs vs trying to swap out a hydraulic throwout bearing.

Everyone's got their preference. It just depends on your taste...

Best of luck on your decisions...

James

Cashburn · #31 (**permalink**) 09-25-2008, 09:32 PM

We've found the Wilwood pulls are pretty good as long as you pin them. If you don't pin them you are asking for trouble. It takes about 500 miles but then... bam.

The Speedway unit is a nice looking piece, and it actually costs less. We've had success with the Howe units as well.

I've got a lot of online evidence that the hydraulic throwout bearings are trouble, but no actual first hand experience. We've had no failures on those we have used, with the exception of one that failed from the start. The fact that they ship with a set of rebuild seals has always left me uneasy. But so be it...

Most important thing is to monitor the fluid and keep it flushed and clean. It is the nature of the beast.

I should add, on our baseline builds the factory supplied slave setup has proven to work quite well. The push nature of it, keeps it away from some of the heat. Now that heatshields are standard on the cars for the masters ... it seems Mr. Lucky's old setup (which happens to be used by another well known and long living replica builder) is pretty damn good.

cbreez · #32 (**permalink**) 09-26-2008, 06:48 AM

If you are already experiencing engagement problems, at this point bleeding won't help...the slace cylinder is already bad (internal rubber deteriorated). Replace to slave (stock Mazda p/u), and completely replace the fluid. I use dot 5, for 2 years now and no more problems. Some don't believe in dot 5 for a clutch, but I have the proof in the pudding...

Any automotive or transmission shop can do it if you don't feel you can...good luck!

Speedysnake · #33 (**permalink**) 09-26-2008, 07:10 AM

I've read through this thread and would like to share my experience with the group. First, I do not challange anything anyone else has said

I had two failures of the Wilwood, pull type slave cyl. on my BDR. The first was due to an installation error and is only relevent in that it got me looking into the system.

The second failure was due to the piston coming loose on the rod, effecting the length of stroke. Each time I worked on it I found blackened fluid in the cylinders

My car had the hydraulic line routed adjacent to the header. I rerouted that. I also added one of the early heat shields that mounts on the steering column. I still had a problem with both brake and clutch fluid getting hot. I added a second piece to the heat shield, providing an air gap and extending to the fender at the louvers.

My slave cyl. was mounted similar to the pics of Jaybars in this thread. After reading many suggestions and watching the operation of the cyl. closely, I determined that this mounting is too rigid, in that the rear face of the cyl. is tight against the bellhousing and the rod needs to move laterally during operation.

I fabricated a mount that attachs to the motor side of the left motor mount. This allows the slave cyl. to float freely between the mount and the clutch arm. See my gallery for a pic.

I have approx.4,500 miles on the car since the modification. I have bled the system twice & found clean fluid in the slave cyl. each time.

Now, with my luck, it'll "crap out tomorrow

CobraEd · #34 (**permalink**) 09-26-2008, 07:23 AM

Convert to a calble and it will work flawlessly FOREVER.

.

JUS BIT · #35 (**permalink**) 09-26-2008, 08:25 PM

Speedy, that's exactly what we do with the external Wilwood Slave. We make a bracket and attach the slave to the rear of the motor mount.

You're absolutely correct, it allows the motor to pivot and keeps the fluid from boiling.

Bests, James

JayBar · #36 (**permalink**) 09-26-2008, 09:10 PM

Speedysnake,

I love your set up. It keeps the slave clear of contact with the engine where it is getting a lot of heat. I could not tell from your picture exactly where you have attached your slave. If your picture was only a few more inches to the left.

But in reality I think re-routing the line and shielding the master helps the most.

Jay B

Speedysnake · #37 (**permalink**) 09-27-2008, 07:39 AM

Jay,

I mounted my home made bracket on the rear capscrew on the motor side (top) of the motor mount. This keeps the slave cylinder moving with the motor, not attached to the frame. It also allows the cyl. to "float" between the heim joint at the front and the clutch arm in the rear. This eliminates any binding of the piston / rod in the cylinder. I agree, the heat problem is a serious issue, so I made a "better" heat shield.

JayBar · #38 (**permalink**) 09-27-2008, 02:28 PM

Speedy,
Now that your describe it I see where it it connected. What is it made from?
It looks like 1/4 inch steel.

Jimbocobra · #39 (**permalink**) 09-27-2008, 02:59 PM

You guys are all terrific, but it does seem everyone has a different opinion (which may be good because several options might work.) I really don't even know what a slave cylinder is. Wish I had a Backdraft Dealer in Chicago. Sounds like the Backdraft Dealers in Texas and Ohio both have great ideas and I am very grateful for everyones input. I already feel better that I didn't buy a lemon and that this is a common problem. I can turn a wrench and follow instructions, but I am going have to get some specific directions. I do investments for a living and this is like me saying to some of you "to design a low cost, option and dirivative strategy - maybe using spreads and stattles to hedge the volitility in a highly concentrated portfolio, while combining other asset classes to increase co-varience, reduce beta and r-squared, increase alpha and drive absolute return. For some of you, you know what I am talking about -to others it is complicated. When you start talking bleeding lines, remounting brackets, hydraulic... My head starts spinning. But that's okay, fixing this is still better than buying a Corvette!
Take care all - I appreciate the help!

6t8stang · #40 (**permalink**) 09-28-2008, 07:42 AM

Quote:

Originally Posted by Jimbocobra

"to design a low cost, option and dirivative strategy - maybe using spreads and stattles to hedge the volitility in a highly concentrated portfolio, while combining other asset classes to increase co-varience, reduce beta and r-squared, increase alpha and drive absolute return.

Um....for the investment-challenged folks, is that the hard way of saying diversify?