Clutch not fully engaging

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Bagged Dually

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Well I'm about to get a truck back that I had sold some family members. It's a 1995 gmc 1500 2wd short bed( I know it's not a square but hopefully you guys can still help). I put a new TBI 350 in it and it's a factory 5 speed truck. I'm guessing it has a NV4500 but I'm really not sure on what the trans is. I put a new clutch in the truck about 2 years ago and shortly after the truck started getting hard to shift. When it gets warm the problem gets terrible. It's like the hydraulic clutch isn't engaging all the way or something. When I replaced the clutch I noticed the arm the throw out bearing sits in was stress cracked inside the area where it pivots on the little pivot ball. I welded it up and got it back to working order.

Anyway where do you guys think I should start looking for the issue at?? Could the arm I welded be screwed up not letting it engage or is it the slave cylinder or something since it seems to get worse as it gets to normal operating temp?? I have little to no experience with hydraulic clutches so any ensight would be great. Thanks a lot guys.
 
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Irishman999

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If I understand this correctly you are having problems with the clutch "dis-engaging", if thats the case I would replace the clutch master cylinder and see what happens.
 

Bagged Dually

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I honestly don't know **** about hydraulic clutches lol. If you want a complete custom air ride setup or a motor built I'm your guy but not hydraulic clutches. I've just never had to mess with one till now.
The best way I can explain it is for example if your at a stop light and have the truck in first you have to keep your foot on the brake to keep it from rolling forward. It's like the slave cylinder is t engaging the throw out bearing far enough or something. I just don't know of the master cylinder can keep the slave cylinder from engaging all the way or if I should just go straight for the slave.
Also how do you bleed a clutch system?? Is it just like bleeding brakes?? Should I try to bench bleed the system first??
 

smurph20

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I know it sounds wierd but check the fluid level in the tranny too.
 

Bagged Dually

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I'll check it as soon as I get the truck back. I don't get the truck back for a few more days. It had the issue before I sold it and they never fixed it. They just parked it and started doing the body work on it. I filled the trans at one point and I remember it took some kind of weird fluid. Does anyone have any recommendations on the type of fluid that trans should use??
 

smurph20

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Synchromesh only made by a couple of companies.
 

bucket

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Most half tons were the NV3500, it has a non-removable bellhousing. If that's what it's got, it has a grease fitting for the clutch fork pivot. Grease it and see if anything changes.

Otherwise, I'd probably replace the clutch master and slave at the same time. It's not that difficult if you know how to bleed them. Install everything, but leave the slave dangling. Then fill it with fluid. While holding the slave with the hose at the top, repeatedly push the rod into the slave. This will force all the air up and out of the system.
 

Bagged Dually

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The bell housing isn't removal able so it must be a 3500. Synchromesh is what I put in it. I remember it was a pain in the ass to find and all I could find was penzoil. I'll try all of this stuff and we what happens. Thanks for all the great info guys.
 

bucket

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In the mean time, driving the truck how it is in stop and go traffic is going to kill the clutch. It'd be best just do drive it on the open road or not at all.
 

Bagged Dually

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I'm supposed to go get the truck about 3 hours away in a few days. Probably 90% of the trip is on the interstate but I might try to trailer it anyway. I just put the clutch in it and really don't want to have to do it again.

Thanks for all this good advice and info guys. Id be lost without it.
 

Irishman999

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You might take a master cylinder with you to get it and change it out before leaving. Usually they are just a couple nuts on the firewall and a hard line fitting. Linkage under the dash is usually simple stuff like a cotter pin through a pin. You should have no problem changing it out.
 

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