89 K1500 4x4 5-Speed w/Off-road pkg 5.0L Sport box 147K miles Bucking in 1`st & Reverse

89 K1500 4x4 5-Speed w/Off-road pkg 5.0L Sport box 147K miles Problem: Slipping Clutch.....Bucking in 1`st & Reverse
I bought the truck twelve years ago. The clutch then had a chatter/
bucking when starting out in 1st gear & even worse in reverse gear. I did a clutch kit replacement two years after I bought it. The bucking was still there..It still does now...always has... So .... I slip the clutch a lot and usually do not use 1st gear...I shift a lot especially when in a freeway back up.... I know it's my fault that a clutch only lasts five years, I'm OK with that...Because this is the third clutch kit in twelve years I wanted to know what was causing the bucking too and fix it right this time...
.. Murphy .. has been kicking my ass ..
Last month I inspected the u-joints. They were good. Most of the seals were leaking. I checked the tranny and engine mounts and they looked good. The rear yoke was a little sloppy. I had all the seals replaced and rear yoke was cinched up to 150lbs.
.. (Murphy) .. The shop mechanic cracked the tranny's tail housing while taking out the old seal with a crow bar. He found a good used housing and delivered it to me that evening with a new seal installed and a tube of RTF.
.. (Murphy) .. Last week I rented The Tranny-Jack from Hell....I think it's older than dirt...I had to stop in the middle of removal to fix the beast......It's fighting me the whole way in and out ... three times in and out so far.
.. (Murphy) .. I rented a slide hammer and pilot shaft bushing puller.....the puller broke and I had to wait till the next day to get another one.
Upon inspection the fly wheel had heat spots, the disk was almost down to the rivets and had two broken damper springs (Damper springs were also broken on the first clutch plate I replaced ten years ago). The pressure plate was also heat spotted. The throw-out bushing was wasted...very sloppy loose. The ball stud looked OK. About what I had expected. The fork tines did not look parallel.
I had the flywheel turned and installed the clutch kit and new fork. I put it all back together and had no clutch pedal pressure.(Murphy) Through the inspection hole I could see the fork just starting to move just before the pedal hit the floor. I thought maybe I had put the throw-out bearing on backwards ... so I dropped the bell housing out far enough to see that the throw-out was installed right. I dropped the pressure plate and checked that the clutch plate was "This side towards flywheel"...it was...I checked the pressure plate finger height (unloaded) and found that the old pressure plate was different....1/8" higher... same manufacture, different part numbers. I called several parts shops & a local Chevy dealer parts guy, They all came up with the same part numbers that are in the clutch kit. So then I replaced the 2 year old slave cylinder. The end of the pushrod was badly worn. (Murphy) I bled the air three times, finally got my old pedal pressure back but the clutch is still not disengaging.(Murphy) I dropped it out again and replaced the kit pressure plate with the old resurfaced pressure plate. Same problem ... the clutch is not being released. I guess that just removing the slave from the bell housing caused it to go bad. Could the new slave be weak...??? (Murphy) The truck was up on ramps so the master and slave were not level... I had to wait two hours until my neighbor was home to help me push it off the ramps. (Murphy) I bled the lines twice more after rolling it off the ramps...No bubbles...The master cylinder was replaced 5 years ago. I don't think it has all of a sudden gone bad too. It was working fine a week ago.???(Murphy)???
Meanwhile the battery died (Murphy)....would not take a charge (Murphy)...Had to replace the battery side stud bolts because my channel locks stripped those little small heads....I hate those 10mm things.....My shoe keeps coming untied (Murphy)...I keep banging my head on the same spot. (Murphy) It seems like every tool I need is out of reach or missing... (Murphy). I misplaced my keys for an hour. (Murphy) ... My phone rings at least every other hour...Murphy is kicking my ass every two minutes .... nothing is going smoothly....And the Rental shop keeps calling to see if I'm still using their $35/day, piece of crap, tranny jack.
Questions:
What could be causing the bucking...???
How far should the release fork travel to disengage the clutch...???
What are the symptoms if I have installed the clutch plate backwards...???...I don't think I did though.
Should I just go ahead and replace the master cylinder too...???..It has not been disturbed.
Should I swallow my pride and tow it to a Pro and pay them to fix it.
Any good, kind advice will be greatly appreciated ...This is very embarrassing.
Thanks,
Churchy
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On 28 Sep 2006 04:56:38 -0700, snipped-for-privacy@nventure.com wrote:

You bucking is likely being caused by chassis/spring wrapup. (what tires size and axle ratios do you have) It would be the worst in first or reverse when drive shaft torque is highest. A K1500 has light spring and if you have a lift with big tires and stocks gears it can kinda wind up and buck as it loaded and uploads driveline torque. Double check slip yoke joint too because it has the most in and out motion in first and reverse. ----------------- TheSnoMan.com
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SnoMan wrote:

No lift kit, MG5 Tranny, 265/75 R16 tires, visual check of slip yoke was smooth with no slop. Glove box tag has 63 options listed...It's loaded...Bucking greatly reduced when short box is loaded.
Thanks for the reply
Churchy
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On 28 Sep 2006 12:18:01 -0700, snipped-for-privacy@nventure.com wrote:

Slop in slip you does not cause bucking, it being tight and binding (not wanting to slip in and out) will cause it to buck and shudder a lot because the axle flexs in springs under high drive shaft torque loads and causes slip joint to move in and out and when it cannot do so freely it can cause your problem. When truck is loaded and springs are compressed it changes the contact area and flexing vs lightly loaded rear axle. ----------------- TheSnoMan.com
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SnoMan wrote:

Thanks again for the reply about bucking. Can you help me with the clutch problem too...???
How far should the release fork travel to disengage the clutch...???
What are the symptoms if I have installed the clutch plate backwards...???...I don't think I did though.
Churchy
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On 28 Sep 2006 17:46:41 -0700, snipped-for-privacy@nventure.com wrote:

This one is kinda easy. First ofcourse the new pressure plate fingers will be lower with a new cluch installed, this is not unusual. THere is a few fix here that will work. one is a longer rod between slave and fork, two, relocate the slave a bit on bellhousing to shorten travel requirement and three, simply find a taller throwout bearing assembly over install a washer or two under fork pivot stud inside bell house. I would try first two before doing the last ones. ----------------- TheSnoMan.com
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Hey Churchy,
Im going off in another direction here, have you checked your spark plugs?
My 90 Blazer will buck when I have a plug going bad, but it usually shows up during a point when the tranny wants to downshift. Bucks pretty good when she does. I know which cylinder is the one prone to fouling a plug and check it right away when I get any bucking.
Charles
snipped-for-privacy@nventure.com wrote:

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Snip
------
Hey Churchy, keep the front of the truck lifted when bleeding the clutch. The bleed screw is on the front, and the filler hole of the master cyn. is also in the front (The old long white version, with a black screw on cap). Air gets trapped in the back of both the master and slave really easy.
Everything will be fine when you get the air out. The clutch doesn't have to move far to disengage. I would leave the truck on the ramps, but you only need enough incline to have all the air escape through the filler cap of the master.
HDS
PS: Been there, done that.
89 4x4 long bed, 5.7 ltr 5speed man
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