Hydraulic Throwout Bearing: How to bleed?
 

How do I correctly bleed a McLeod Hydraulic throwout bearing?

I fired up my Cobra for the first time today (YAHOOOOOO!!!). Straight headers, no mufflers---just wanted to introduce myself to the neighborhood. Cobra runs great, and it was a thrill just to hear some life in it after working on it for so long.

However, I don't know what I'm doing when it comes to bleeding the hydraulic throwout bearing. I pumped it up, first by hand from under the car, and bleed the Tilton master cylinder first. Then I had my brother pump the clutch slowly from inside the car (I've only got two hands...). He'd pump it, and then I bleed the air out (not absolutley certain I got all of it, but...).

Am I doing this right?

I keep thinking that if he holds the clutch in, this should be pushing the HTB out, but if I release the pressure by bleeding it, the HTB is going to collapse first (as opposed to the pedal pushing in).

I'm not sure the "brake bleeding method" will work in this case.

I'm confident in my setup. I measured and adjusted the offset myself. I have the "bleeder line" on the top of the HTB, so presummably air would go up to the bleeder line.

Need some expert advide, or at the very least some sort of acknowledgement that I'm doing this correctly and just need to patiently continue.

Thanks in advance for your help,
Cheers
Dangerous Doug

And yes, the Cobra was REALLY LOUD and I LOVED IT!!!!

Doug,

If the clutch fingers depress, that's a good thing. ;)

When the bleeder is opened, the release bearing will push the air out, the same way that the air will be pushed out if the pedal is depressed.

Doug, I welded a bracket on the outside of the bell housing (see pics) and attached the bleed end, slip a piece of clear hose over the bleed end and the other end in a jar, just let it bleed itself, works great. I do the same for brakes.

Nice setup, Perry.

The best way to bleed anything is with a pressure bleeder. Clean, one person, effective.

Roscoe

Doug,

I found this FAQ on the McLeod site. It sounds like you cycle back and forth between the master cylinder and the bearing.

"Bleeding should be done first at the master cylinder and then the bearing, then the master and then the bearing again."

http://www.mcleodind.com/faq.html

The pressure bleeder is probably the best be to drive all of the air out of the system.

I like the bracket idea. Having the bleeder line hanging there freely bugs me. It'll make it easier to manage the bleeding process as well.

Sounds like I had the right idea, but I think I'll pick up a pressure bleeder. Then, master, slave, master, slave on the bleeding. Two tubes, and a catch can of some sort.

Back under I go. I also need to look at the throw requirements. Doug at ERA suggested about 1" with my Tilton master cylinder. I have it at about 1-1/8" right now. I can go with a longer throw, but I don't want to overextend the HTB (yuck! What a mess that'd be!)

My clutch is the "Ford Long Style", so I'm wondering if this takes more throw than a diaphram type pressure plate.

Back under I go...

DD

One thing to remember: The car must be level or tail-high to get all the air out of the master cylinder. Nose up = no good.

Bob: Excellent point. It was nose-up yesterday during a second "bleed attempt". I'll make sure the back-end is up (kind of like the picture in my gallery...).

Also, I purchased a bleeder tool today, which will allow me to bleed the slave cylinder from up above. Ah, not laying on my back squished between my creeper and my Armando oil pan...

DD

Doug ... sounds like between the McLeod instructions, pressure bleeder, clear tubing & bracket, you should be able to get the air out of the system and get full range of motion from the clutch.

What I use for a catch bottle, is a clean dry water bottle taped to a brick or block of wood and an long piece of clear vinyl tubing. That way, you can see the air bubbles in the tubing and you won't tip over that catch bottle, it saves a lot of clean up.

- Tim

I extended the bleed hose about two feet and extended it up where I could get to it from the engine bay. I then have a helper,(my son), pump the clutch pedal while I open and close the bleeder. You do the clutch the exact same way you do your brakes.

I set mine up similar to Tim. I connected a 2 ft piece of braided SS hose to the throw out bearing and put the bleeder on the other end of the hose. The bleeder is now just beside my remote fluid resevoirs. It is very easy to bleed as you are actually standing beside the car. Once I was finished with the bleeding, I attached it to one of the reservoirs with a plastic tie wrap which you cannot even see unless you are really looking for it.

One more tip, make sure that there is absolutely no air in the hose between the remote reservoir and the master cylinder as it will only be a matter of time before that air gets sucked into the master which will then have to be bled again. :mad:

Wayne

Purchased a pressure bleeder, and then climbed under and bled it out pretty well.

Now I feel some good pedal! Can work through the gears easily when I push in the clutch.

Try it out on Saturday. May need to adjust it slightly, but we'll see.

Doug

Great news Doug!! One step closer!

Doug: Swing by on Saturday if you get a chance. Wrenches start turning at 11.

DD

Like I said, pressure bleeding is the way to go. Glad to hear you solved the problem.

Roscoe

Muchos Gracias!

DD

Will do. I'll give you a call. If I come back from breakfast on 17 it might be bit earlier than 11.

Doug, you and I are at the same spot. I pressure bled my TOB this week. First start was last Sunday. I don't know much about ERA's but with my FFR I have to create a pedal-stop. I've heard that if the pedal has too much travel you can over-extend the TOB and oil down the clutch. So you may have to limit it's travel. I don't know if your ERA has one already but I thought I'd mention it...

:)

Same thing on the ERA, but the throw on the clutch pedal is such that from pedal to firewall gives about 1" of travel on the Tilton master cylinder. I essentially use the firewall as a pedal-stop.

I adjusted mine so that I have about 1-1/8" travel at the MC, and will likely give it an adjustment on Saturday to line the clutch pedal up with the brake pedal more precisely.

Yes, overextending the TOB would be a messy disaster!

Doug