Changing a Clutch on a Backdraft
 

Ok, a friend of mine cannot get his transmission in gear if the car is running. We suspect the clutch is bad. What is involved in changing the clutch? More my ERA the tunnel came out allowing access. Can you get access to the transmission and Bellhousing from the top or do you have to do it from the bottom? Are there any other things likely to cause this? He had been gradually having a great difficulty in shifting over the past few months so we adjusted clutch like 2 turns on the adjuster. Worked fine for a few weeks and now he cannot get into gear with car running. Looking for answers before we tear into it.

Phil

What kind of throw-out bearing? Might look at that, or fluid levels, etc.

That's a typical symptom of the clutch is not disengaging completely and still powering the input shaft on the transmission. I would see if with the clutch engaged (pedal up) the piston in the slave cylinder is pretty much fully bottomed out so that he gets a full stroke when pushing the clutch pedal in. If he has a hydraulic TO bearing then except to try re-bleeding it, he will just have to take everything out and see what's worn.

However, as a clutch wears the pressure plate fingers move slightly to the rear, taking up free play at the top of the pedal. At some point free play is gone and the clutch slips or clamping pressure is reduced to a level where the clutch slips. So failing to get full disengagement should not typically be a problem of a worn clutch unless he over-compensated in adjustment for it.

My guess is clutch is out of adjustment/needs bled, etc.

Agree with Blykins, the BDRs have had heat issues with the hydraulic clutch system which causes problems with the master and/or slave. There's a heat shield that mounts to the bottom of the master that helps. Also yearly flush and bleeding with high temp brake fluid (Wilwood) helps. The clutch is accessed through the bottom, not thru the tunnel like an ERA. Good luck.

It's clutch hydraulics, not clutch wear...don't worry about transmission.

Had the same problem...many times...95% slave is at fault!

fought slave cylinder issues for many years on my Backdraft. My first failed third day of ownership! LOL I did not find heat being an issue, hell std brake fluid boils at 450*F...that is hot! anyway

IMHO, It is a slave cylinder that only uses a single U cup seal. Switched to a dual seal on the slave piston (one U cup and one O ring) have never had to bleed it in 4, maybe 5 years! B4...had to bleed 2 - 3 times a year. You can probably machine an "O" ring groove the the piston you got. The other issue is the bleed, at least on mine was on the bottom...:eek: so, I did a new mazda slave that had the bleader on top. I think I put the P/N on this site.

worked 4 me...but one man's food is another's poison...

found my post for 2007...the unit is a 1988 mazda L4 2.2 liter is the one that came on car #260, (advanced auto parts #0728342, this was the number on 9/18/2006, also, the 2.6 liter is a top bleeder version).
My slave failed because of overstroke, according to the Backdraft boys in BB, Fla. They sent me a new one, this ones seal was in bad shape, didn't even use the new one. My failed seal was in better shape. Honed the slave cylinder because of a sever out of alignment of the cylinder to the fork,...this caused the push rod to rub on the bore, plus the over-stroke...caused leakage, draining all fluid overnight. Adjusted the stroke and its been 6 months on the re-aligned slave and honed unit...still good. BTW...stroke adjustment are the nuts on the shaft from the clutch petal to the master cylinder. If you get a replacement, I'd dissassemble it look at the seal to make sure it has a good lip and the bore looks good. Hope this helps.

Thanks gents. It appears that it the clutch slave cylinder which was leaking much on engagement. He is picking up the part today with a likely change tomorrow.

Phil

Mis-alignment does seem to be a common enemy of these hydraulic cylinders. One of my brake masters leaked almost immediately upon getting it on the road and I found the bore scraped up where the piston had been rubbing on it. It's kind of hard to get a good alignment on the clutch slave because the fork moves in an arc as it's depressed - especially if the rod is fairly short. About all that can be done is to try to shim and center it as much as possible.

I ordered a slave cylinder from Rosehill Performance and the push rod from him. The pushrod is adjustable allowing the proper adjustment to the clutch via the through out bearing. I also installed a remote clutch master cylinder from Summit (cheaper than form Backdraft) and an aluminum reservoir and had a stainless line made by BAT in Sarasota, FL. I send the the rubber line and he made a AN3 stainless line with the correct fittings. Took a little work but now my problems seems to be over.

If you can please post a couple of pics and the PNs you used. It will def help me down the road...
Thanks.

I'm in Ocala from time to time.

I used the Wilwood 3/4" part #260-6089 master cylinder and got a AMP billet clutch reservoir from Ebay for $99.00. Looks cool and works well and holes plenty of fluid. The braded line was made by BAT in Sarasota. Rosehill performance makes the slave cylinder kit for both the T5 and the Tremac Trans. I used an AN 3 line from the master cylinder to the slave and the reservoir. The correct fittings and lines can be had from BAT.

I'm experiencing similar issues to all of you since my car was new.

I'm use to banging gears pretty hard and fast in most of my cars. However, this damn backdraft.....

Since new, the 1-2 shift has always cause me issues and ground the gears. Syncro is now F'ed I'm sure of it. Always have to wait til the fluid is very warm to start hitting that first shift very hard.

This is my 4th car with a tremec 6 speed. And honestly, its the same motor (coyote) and trans you get in a mustang.....yet it shifts 5x slower.

How do we get this fixed so the shifts are not so notchy and butter smooth like a typical production car?

Also, is anyone's clutch feel like you're pushing a sled fulla old train parts through sand? My god, is it HEAVY...so much so, it hurts my foot to drive it with sandals on if I have to hold the clutch in. I have a clutch that holds 1,000hp in another car, and its half the effort of this one.

The T56 Magnum is NOT the same trans as a Mustang. The Mustang uses a Getrag box, the MT82, not a Tremec.

Alignment of the pushrod is very important, you want minimum in-out/up-down movement when activated. This is hard to achieve as the clutch arm swings in an arc but it can be held to a minimum with proper design.

Thanks guys, replaced the slave cylinder and adjusted the clutch and it worked great.

Phil

Correct - I wish my 2012 GT had a Tremec. The Getrag is a balky gearbox. Shelbys get a Tremec I believe.

MJC, sounds like you have a mismatch between your master and slave cylinder sizes. If you are using an external slave what is it's bore size? What is the M/C size? They should be roughly the same.

As an aside for others with BDR clutch problems: After multiple M/C and slave changes (and trying to bleed them) I completely bypassed the BDR hard line and, like one other on this thread, used #3AN line. This did 2 things for me; #1, allowed me to reroute the fluid path and #2 allowed me to completely bleed the system out of the car on my bench so that when I installed it (dropped right down through the top) all I had to do was install and adjust it. No bleeding once it was in the car.

Top bleeding the system is pretty easy and you can do it alone.

You'll need a Rubber stopper to fit the reservoir opening. A #10 stopper works on the Willwood master cylinder.
Preferably use EPDM rubber as it is compatible with brake fluid but any will do since it is a momentary contact issue.
Using a brake bleeder hand vac pump connect to the stopper you placed in the reservoir neck with a short piece of hose.
Pull a vacuum with the pump and maintain it for 1 minute (max vac you can achieve).
Release the vacuum and pump the clutch pedal full travel 4-5 strokes.
Repeat the vacuum/pumping cycle 5-6 times on a empty system will typically bleed it fully.

EPDM Rubber Stoppers: solid, 1 hole & 2 holes | WidgetCo
MossMotors.com - Restoration Parts And Accessories For British Cars

Maybe I'm missing something but that makes absolutely no sense to me at all. Can you do a video of the process or something?