Project: Tetanus Shot - 1948 Willys

[YJJPWrangler]

I keep seeing online where some people are having the same issues as me with regard to the clutch not disengaging. Apparently there were two types of forks, a cast and a stamped one. I have the cast one. The only discernible difference between the two is the attachment point for the slave is further in towards the transmission on the stamped fork. @getstucksome came over last night and helped brainstorm. We decided to drill a hole further in(1" in) on the stamped fork to see if that made any difference in travel. No difference at all. I am still getting 5/8" worth of travel out of throwout bearing using this slave cylinder. I can manually cycle the slave and I'm getting about 1 1/4" of travel I have yet to find online or in a manual how much throw is required to disengage the clutch.

I have the clutch torqued down again. My plan is to install the transmission and bled the slave. Apparently, it is common to have to cycle the slave 40-50 times to bleed even if no bubbles are present. When I first bled it, I gravity bled the entire system and then used a one man bleed pressure gun to put pressure on the line before I opened the bleed nipple. I'm assuming this is the best way. The master has been bench bled.

 

[rockcity]

I still think your slave is too short.

I still think you should replace the slave with all thread and adjust it until the clutch releases. Measure that distance and it will give you the amount of travel you need on a slave cylinder to disengage the clutch.

 

[a_kelley]

If you moved the mount point in towards the trans, you should get more throw at the expense of operating force. (Shorter on the cylinder side. More throw, more force)

Bleeding with the one man bleeder, was that reverse pressure or vacuum or a catch bottle? I usually will take a rubber cap with a hose barb through the middle to my hand held vacuum pump and pull vacuum on the whole system from the reservoir and it'll pull all the air out the top, and when you release the vacuum, the fluid flows back.

 

[YJJPWrangler]

@a_kelley I'ts a vacuum bleeder. It's a pistol pump with a gauge attached to a catch can that then goes to whatever you are bleeding. Pump the pressure up then open the bleed nipple until fluid/air bubbles start flowing. Keep repeating etc etc.

I have this one.

Advance Auto Parts - Down for Maintenance

 

[a_kelley]

Repurpose it by using a rubber lid with a barb in the center run to the catch can to the pump and pull vacuum on the top with the bleeder closed. Works great, but takes a minute to pull good hard vacuum (26-28" hg) and you can usually watch the air come out in the resi.

 

[YJJPWrangler]

Right now the slave is completely empty. I have always bled from the top down. I think I need to continue bleeding from the top down to get the slave filled up first.

You are saying to bleed from the bottom up right? Attach the pump to the master and bleed up(assuming the slave is mostly full).

 

[a_kelley]

You can fill the resi, bleeder closed, pull vacuum on the resi and the vacuum will pull the air out, when vacuum released, it'll fill with fluid. You can bleed it at the bleeder first if you want to. I've just found pulling vacuum on the resi to work pretty well.

 

[YJJPWrangler]

Sounds good. Called Novak today and the guy on the phone stated that most clutch applications require about .55" of travel to release the clutch. I am getting 5/8" travel at the Throwout bearing. This should mean that I have enough travel both in the throwout bearing/slave to disengage/engage the clutch.

I'm going to install the trans tonight, use some threaded rod to engage the T/O bearing per @rockcity and bleed the slave. My plan is simple. I'll hold the clutch fork against the pressure plate to disengage the clutch. With the transmission in gear and the clutch fork depressed, I "should" be able to rotate the output shaft of the transmission.

This should rule out any and all T/O bearing movement. I'll then add the slave into the mix to see if it continues to work or doesn't work. If I'm not getting enough movement from the slave, I'm thinking it should be the master not providing enough volume to the slave.

 

[a_kelley]

Also double check the pilot bearing/bushing...

 

[YJJPWrangler]

Pilot bearing/bushing is good/new. There are some light surface scrapes on the outer ring from installation but nothing deep or concerning. Anything else to look for with the pilot bushing?

 

[a_kelley]

You could throw the trans up in there with the clutch not installed if you want to check if it's binding. Light coat of grease won't hurt it.

 

[paradisePWoffrd]

are you bleeding the slave with it installed in the jeep and under pressure from the clutch?

I had a similar issue with a Toyota once. I gravity bled and vacuum bled. Had a firm pedal but it would not travel enough to disengage the clutch.

I eventually had to remove the slave in order to allow the piston to push out completely and the cylinder to fill all the way with fluid. I bled it while attached to the line but disconnected from the clutch fork. In order to put in back in the truck afterwards, I had to manually compress the clutch enough for it to slip in.

 

[YJJPWrangler]

are you bleeding the slave with it installed in the jeep and under pressure from the clutch?

I had a similar issue with a Toyota once. I gravity bled and vacuum bled. Had a firm pedal but it would not travel enough to disengage the clutch.

I eventually had to remove the slave in order to allow the piston to push out completely and the cylinder to fill all the way with fluid. I bled it while attached to the line but disconnected from the clutch fork. In order to put in back in the truck afterwards, I had to manually compress the clutch enough for it to slip in.

This might be the culprit. I did bleed it while it was attached to the transmission. I didn't get to work on it last night but will work on it tonight.

 

[YJJPWrangler]

Last night a good friend of mine came over and we set out to diagnose and fix the clutch issue. I walked him through the math plus everything I have already checked: clutch, throwout bearing, slave etc. We decided to throw the transmission into the jeep. Got it all bolted down and lined up pretty easy. Amazing what having an extra set of hands and eyeballs will do with productivity.

Once we got the transmission installed, it was time to manually move the clutch fork. We installed the shifter and put it into first gear. I sandwiched a 2x4 in between the clutch fork and the bellhousing and used a pry bar to try and move it. No dice. I could feel the throwout bearing hitting the fingers but couldn't press it in enough to disengage the clutch and turn the output shaft on the transmission. We then took a ratchet strap and hooked to the clutch fork and antiwrap bar. Success! . I'm so glad I don't have to buy an expensive adjustable throwout bearing or change out the fork. This proves my math was correct We were able to disengage the clutch and spin the output shaft while it was in first gear. There was a noticeable amount of clutch fork movement once we finally got it to engage. I guess it being a new clutch/pressure plate it obviously isn't broken in yet. We took a measurement on where the clutch fork needed to be to disengage the clutch and adjusted the slave down to work.

We then started bleeding the slave with it not attached per @paradisePWoffrd (great suggestion BTW!). We did a variety of bleeds, we started with gravity bleed, then switched to a one man bleed, and then finished up by pumping the pedal. We were able to get full travel out of the slave(1 1/4") with a good firm clutch pedal. About the time that we were going to hook the slave up to the transmission, I noticed that I was only getting a half pedal press with a very hard stop in the pedal about halfway down. We figured that there was a air bubble still in the slave. So, bled it some more, got crystal clear fluid out no bubbles. I could pump the pedal 1 to 2 times with full pedal stroke and then it locked up halfway again. Repeat the bleed process, still the same. 1-2 full pedal strokes after bleeding and then a hard stop at 1/2 pedal(note that the slave was not hooked up to anything at this point)

The only thing that both of us came up with is a bad cup seal at this point. I bought the slave almost a year ago from Summit but obviously am just now hooking it up and using it. I cant think of anything else that it would be? I don't think my slave is rebuildable either. The reviews on Summit aren't great but I figured Wilwood makes good products so this should be a good one. I am going to call Summit today to see what they can do for me. It was only $80 but if I can return this one that would be great. Summit has always had really good customer service so we will see.

Other news, I got the transmission crossmember installed again and bolted down. It's a tight fit and requires a lot of prying to get all the bolts lined up. I have not installed the transfer case yet. I still want to add an oil sight tube to the D300. Also the extra space that I have with it out right now will allow me to finish welding the exhaust, add some exhaust hangers and get a better routing for my electrical wires. My battery will be in between the front seats and I have the battery cables running down the inside of the passenger framerail. I need to protect them from the exhaust heat and along with my friend and @getstucksome suggestion, I'm probably going to run them down the outside of the frame rails tight to the body. Or I can run them through the old heater hose ports in the firewall on the the passenger side but I'm undecided if I like that route or not. I'll have to reconfigure some of the wires but it shouldn't be too terrible.

Edit: Summit racing customer service is kick ass. They warrantied it and will be sending me a new one at no cost with a box/return label for the bad one.

 

[YJJPWrangler]

Well, no dice. Got the new slave cylinder in and bled. Still the same issue. I get great throw for the slave for 2-3 pumps of the clutch pedal and then it stops halfway down. Hold the pedal down, crack the bleeder valve, pedal goes to floor. No air bubbles in the lines at all during bleeding. After bleeding, I get the slave travel that I need(for 2-3 pumps) and then its back to halfway. I even threw the old slave back on, bled it, and it is doing the same thing. The only thing I can think of now is the master not having enough volume to move the slave. I believe I have a mid 90's YJ slave. I'm looking at upgrading to this unit. 1" bore, 1.4" travel. Too much throw/bore size or should be good?

https://www.summitracing.com/parts/wil-260-6766

 

[a_kelley]

I'm thinking you have something mechanically binding if the pedal stops halfway down & hard.

 

[YJJPWrangler]

I'm thinking you have something mechanically binding if the pedal stops halfway down & hard.

The slave is not hooked up to anything at this point. The only mechanical piece is the connecting arm from the clutch to the master cylinder. Everything else is hydraulic.

 

[R Q]

You can't go wrong with a new MC. As long as it's compatible with your slave. I guess you have reached the limit of the YJ master. On the good 2-3 pumps does it actually engage/disengage the clutch?

 

[McCracken]

I think you're MC is boozed up. That or the linkage to the MC is binding.

 

[YJJPWrangler]

I think you're MC is boozed up. That or the linkage to the MC is binding.

Thats what I'm thinking. Probably going to order a new one in a week or so.

 

[YJJPWrangler]

Ordered a new MC from Amazon yesterday, should have it in hands today. Hopefully this fixes my issues.

 

[YJJPWrangler]

Well the new MC didn't solve the issue. I'm still getting the same issues with the new MC that I was getting with the old one. After about 2-3 pumps of the pedal, the pedal locks up halfway down.

Right now, I have the slave not hooked up to the transmission and have alternated bleeding everything by either the pedal or manually moving the slave in and out. After 2-3 pumps of the pedal(with the slave traveling all of its stroke), the clutch pedal stops halfway down and locks(with the slave being in the max pull spot). I'm pretty sure that the slave is not returning to its normal extended position after every stroke and is thus "short stroking" itself.

My plan is to call Wilwood today and see WTF this is an issue. There is no binding at the pedal assembly, the pedal swings freely and smoothly. I'm running all Wilwood components as well.

In other news, I hooked up some backup lights that a buddy had given me for Christmas last year. They are Alpena light pods. Drilled and tapped into the rear bumper and got them hooked up to my switch panel. They are bluetooth capable and you can change the colors if you want. They also tuck up nicely under the rear tailgate and are super bright.

 

[a_kelley]

Right now, I have the slave not hooked up to the transmission and have alternated bleeding everything by either the pedal or manually moving the slave in and out. After 2-3 pumps of the pedal(with the slave traveling all of its stroke), the clutch pedal stops halfway down and locks(with the slave being in the max pull spot). I'm pretty sure that the slave is not returning to its normal extended position after every stroke and is thus "short stroking" itself.

hook it up and try it! The slave won't retract on its own. It relies on the linkage/pressure plate to compress it. If you compress the slave fully (removed), how many pedal strokes does it take to fully extend? Then compress it and reinstall it and see if it works. (Or the opposite way if it pulls vs pushes.)

 

[YJJPWrangler]

hook it up and try it! The slave won't retract on its own. It relies on the linkage/pressure plate to compress it. If you compress the slave fully (removed), how many pedal strokes does it take to fully extend? Then compress it and reinstall it and see if it works. (Or the opposite way if it pulls vs pushes.)

Ok that makes sense. Right now it is hooked up to the transmission but it is already short stroked itself. So I need to crack the bleeder again. I can cycle the pedal 2-3 times before I start to notice it short stroking. After about 4-5 pumps, the pedal stops halfway down.

 

[a_kelley]

Ok that makes sense. Right now it is hooked up to the transmission but it is already short stroked itself. So I need to crack the bleeder again. I can cycle the pedal 2-3 times before I start to notice it short stroking. After about 4-5 pumps, the pedal stops halfway down.

once it fully extends (not installed) you should barely be able to move the clutch pedal and it stop hard. (This will prove air out of the system). When installed, the slave should take up all the linkage slack and then only actuate the pressure plate, and that's where you should get your pedal resistance, since the pressure plate will be pushing the slave back in.