Slave cylinder mounting and adjustment questions

[lippy]

I just received my engine from Brent yesterday and am getting ready to drop it in this weekend. I'm a bit unclear about the slave cylinder mounting and adjustment, so I'm hoping for some color and clarification. As you can see in the photos below, interference between the slave and the edge of the bell seems to prevent the slave from being concentric with the hole in the fork. No big deal, I can grind down the bell a bit. But I want to make sure I get the mounting and adjustment right.

My questions are:

1 - After I grind down the edge of the bell, should I just eyeball the rod and fork to get them very close to concentric, and then drill and tap a couple of holes in the slave mounting bracket and block flange?

2 - From the photos, does it look like I need the ERA spacer (they didn't think I would)? What is it's purpose?

3 - I will cut down the threaded rod. Doug also recommended I use it to push back the plunger in the cylinder all the way, and then back it off 1/4" so there is play between the cylinder and the fork. Not sure I completely understand, so any additional color on how to adjust (and mount) this would be appreciated

4 - Do most people use a spring? If so, what type and tension?

[jhv48]

Two schools of thought here. Those that swear by free play, and those that don't.

1. No return spring is necessary, and no free play is needed. Mustangs have been using this method for decades with no throwout bearing failures. Push the rod all the way into the slave and then adjust the rod so that it is pushing against the clutch fork. No free play. The fork rests on, and applies pressure to, the throwout bearing. Mustangs have been doing it this way successfully for decades.

2. Attach a return spring to the clutch fork and attach the other end to your slave bracket thus negating the constant pressure your slave exerts on the fork and thus the throwout bearing.

Both work just fine and you will get people who swear the other way will lead to an early clutch failure. Not true. I have the no-return-spring setup, as do most SPF cars and have had no clutch problems in 17,000 miles of driving.

Make sure you round the end of the rod that fits into the slave and try and get the slave and rod to push the fork in as straight a line as possible. Also, make sure your fork travels about 1 1/3 inches. That should be enough to successfully disengage the clutch. If much less than that, you might need a bigger master cylinder or smaller slave cylinder to get more travel. Easy to test. Start the engine and see if you can engage reverse without grinding or excessive effort.

[DanEC]

Lippy - you want the slave and rod working the fork in as direct alignment as possible. From the top picture it looks like it is well aligned. If it looks as good from the side, I don't think the spacer will do anything for you. If you only have to grind a very slight amount from the bellhousing - as much as you may hate to touch it, I think that will give you the most satisfactory operation.

From memory - I think the bellhousing hole on my Ford block daylights through there. I carefully adjusted bolt lengths and was able to screw the spacer into the backside of that hole. Looks like you will have to do some drilling and tapping.

The slave cylinder needs to be shoved all the way to the front of the motor by the pushrod. You don't want but a few thousands of movement left. I am using a spring on mine. I don't know if it's really necessary. I'm an old mechanical clutch linkage guy - just doesn't seem right without a spring to keep the throwout bearing slightly off the clutch fingers. I think it's kind of up to you and whatever you think makes sense. Without a spring, there is definately enough pressure from the slave cylinder spring to keep the bearing in contact with the clutch.

I don't seem to have a picture of my installation with the spacer.

[DanEC]

There is a picture of the spacer on Patrick's car in this thread.

Clutch slave cylinder rod length ?

[blykins]

Jeff,

You want clearance between the throw out bearing and the pressure plate fingers. No preload, no touching. There are bearings that are made to sit against the pressure plate and ride, this is not one of them.

If you don't have enough room to adjust the slave and get some clearance, there is a little spacer block underneath the clutch fork mounting bracket. It will give you another 1/4" or so of clearance by placing the clutch fork and bearing further away from the pressure plate.

From the pics, the alignment doesn't look that bad. Remember, when the clutch fork goes towards the rear of the car, it will swing in a slight arc, which will help align things.

FWIW, I would also use a return spring. In the overall scheme of things, you can set the clutch up to your preference....whether it starts to disengage at the top of the pedal throw or deep down....but in any case, I would make sure that the bearing doesn't touch in the clutch pedal out position.

[patrickt]

Originally Posted by DanEC

There is a picture of the spacer on Patrick's car in this thread.

Clutch slave cylinder rod length ?

Yes, ERA sells a custom block of pre-drilled aluminum that sets the slave back and aligns it up. I can post a thousand pictures, if need be....

[lippy]

Thanks for the quick responses. All very helpful. For the return spring, is it just a light pressure throttle-type spring, in a length that fits?

[patrickt]

Originally Posted by lippy

Thanks for the quick responses. All very helpful. For the return spring, is it just a light pressure throttle-type spring, in a length that fits?

Pretty light spring -- it's not like the bears that you had to put pennies in between each roll of the spring in order to spread it out. You can just do it with pliers. BTW, make sure you trim the end of that fork before you put it in the car. I have a long thread on that. ERA started doing it after my thread.

[patrickt]

Here's the fork trimming thread: So, Should I Replace This Part or Not?

[ERA Chas]

Originally Posted by blykins

Jeff,

You want clearance between the throw out bearing and the pressure plate fingers. No preload, no touching. There are bearings that are made to sit against the pressure plate and ride, this is not one of them.

IIRC, I ran .040" between a fresh disc and plate. Made an aluminum strip tool (.040" thick) with about a 45* bend to get between and measure. Goes in the fork hole. And yes, run a spring.

[strictlypersonl]

Lippy,

Did you talk to Doug today? He wasn't aware that you had an aluminum block. The sometime require a special adapter for the slave adapter. See page 36 of the manual.

[DanEC]

If the space between the fork and the slave cylinder is a little tight to get the rod in with some clearance for adjustment I would consider some type of spacer between the block and the slave cylinder bracket rather than removing the spacer from under the fork pivot bracket in the bellhousing. You want the fork spaced pretty well forward in the bellhousing opening so you don't run out of clearance for full travel.

I'm curious why ERA supplies that long, built up rod nut on some builds and just the acorn nut on the end on others like mine. I guess I have clutch rod envy.

[lippy]

Thanks for all the help. I think I got it. I had to grind off part of the bell for clearance, but I touched up the paint after. Then I ground the front of the block flange level, and drilled and tapped two holes. I leveled the engine and then leveled the slave, and eyeballed it for lateral alignment. It seems to be pretty close. I also ground off some of the fork (thanks to Patrick). Once I have a spring on there will be enough room to allow for about 1/8" of play, maybe a bit more.

[DanEC]

Looks good - good luck with the install. When I installed the slave cylinder hose I didn't think about keeping the salve cylinder rotated with the bleeder valve at the high point (details, details - there's that mechanical clutch linkage background again). Drove me crazy trying to bleed it until someone pointed it out. Looks like you have yours at the top.

[DanEC]

You may want to think about taking a dremel or cutoff tool and grinding a screwdriver slot in the end of the rod. It's something I wish I had done on mine (and I still intend to) to simplify adjusting the clutch clearance.

[prp289]

Did you make the bracket for the slave cylinder? I have the cylinder and bracket from ERA except the bracket is for a Lakewood and not the Quicktime I have.