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91wranglerbase 01-07-2011 07:51 AM

Clutch problems - big issue????
I went to drive my 91 4.0L wrangler today. Ever since it has gotten cold (lows in the 20s & 30s here) I have noticed that many times if I don't let the jeep warm up I have a problem with the hydraulic clutch. It acts like there is air in the line somewhere, although I have bled the clutch line, etc.

The symptom is that after cold startup, I step on the clutch pedal, and the line pressure bleeds out, causing the clutch to engage and send me towards the garage wall or backwards. Jam on brakes and choking down the motor is about the only way to stop it.

This morning it did it twice, in reverse. After the second choke down I couldn't get the jeep started again...hopefully it just flooded.

Questions are:

1. Is the loss of line pressure against the clutch more likely due to the clutch master cylinder or is is the throw out bearing?

2. How much is a good ballpark average for a clutch rebuild professionally done?

3. How would I know if my jeep jumped time or any thoughts on trying to get it started again? I had to leave the jeep halfway in and halfway out of my garage this morning, no chance to push back in because of the grade of my driveway.

91_Utah_YJ 03-06-2011 10:25 PM

Shame on everyone! No response to this well thought out post? I'm having clutch? issues and will be making sure to post a thread letting everyone know what the issue and problem resolution was... Where are all the people who've had issues similar to this???

gennybro 03-07-2011 06:53 PM

got a price from a garage on friday to replace clutch and slave cylinder in my 91 yj,2.5 cyl for 650 dollars.

91wranglerbase 03-07-2011 07:35 PM

Utah YJ, Your jeep looks sharp in the avatar above, what kind of lift do you have?

Hey thanks for replying to this post. I should have replied, I ended up answering my own questions re: the jeep's clutch. Fortunately for me, my issue was the clutch master cylinder. Before taking it in for a full clutch repair, I decided to replace the clutch master cylinder first. I bought a replacement clutch master cylinder from O'reily for about $40. It took about an hour (well an hour and a half, see below) to replace the stock unit. The new master cylinder is metal body, whereas my factory one was plastic. The master cylinder gravity bled for the most part, and after purging the line of air I have not had any additional problems with fluid level or clutch pedal pressure.

Tip: purchase an inexpensive metal punch in the same diameter as the roll pin hole while you are at the auto parts store. The hydraulic line has a pressure fit bung with a rubber o-ring; the roll pin is driven in over the lip of the bung to seat the o-ring into the master cylinder. The roll pin is about the same diameter as a finishing nail, which might also be used to drive out the pin from the old master cylinder. BE CAREFUL not to drop the roll pin; I may have just been jipped but my new master cylinder didn't compe with a new pin, so I had to reuse the pin. I dropped it twice trying to drive it back in to place, took me more than half an hour to fish it out from the inner fender below. You might prevent this by using a bit of masking tape to tape the pin to the end of the punch to start it back in to the hole.

If you are losing clutch pedal feel, you may want to try the master cylinder first; for less than $50 its good preventative maintenance anyway if you are still on the original unit, and it might fix your clutch engagement issue at least until you can save up for the clutch you'd like to have and getting put in by the right shop.

As per the starting issue i had above, I must have ended up in a flooded condition, although I don't know how that would be possible with cranked right up in the evening when I got home that day.

91_Utah_YJ 03-08-2011 01:38 AM

Thanks for the information on the CMC and the compliments too!

I just bought this in mid February and haven't been able to determine what brand it is. It's a 2.5" suspension lift and a 2" body lift. Looks like there's plenty of room for 33's (sitting on 32's right now). I've installed new shocks and have some prothane greasable spring and shackle bushings arriving wednesday.

I'm new to wheeling and figure I'll play with what it's got before making any major adjustments, but I'll make sure to let you know how she does on some utah trails the next couple of months.

As far as the update on the clutch goes after posting that comment Sunday night I hopped outside to pull it into the garage and look at it some more when I noticed a whining sound when I clutched. From most of the friends I talked to I've gathered that it could very well be the pilot bearing or a leaky slave cylinder. I have a small leak near the rear main seal as well that's going to warrant a new plate and disc so clutch kit here I come.

Having never replaced a clutch before, and needing this thing running to get to and from work, I've decided to take it in to my mechanic and get it done professionally till I can befriend some folks who have both the experience and the time to help out!

I'll be sure to let you guys know what the verdict was.

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