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71K5 - BP71K5's Just for fun build

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Thanks, where does the shifter come up out of the tranny cover? I'm curious cause the tranny shifter hole is right on top of the old x-case shift hole. (Just remembered I can look at your pics. :))

ORD said that alot of people are running with this setup. I actually fabbed up the x-case linkage so all I need is the shifters and mounting brackets. I should remember now to call around first. My wacky shifter idea still might work, but it's going to take a while to fab and figure out. I wanna drive this thing soon.

I did take the hurst shifter apart and figured out what needs to be modified. Two of the shift levers need to be ground for more clearance to the others. It's actually a pretty simple mechanism, but they used hardened steel so it's not as easy to drill out. I had to go get some carbide grinder and drill bits. I'm also going to have to weld in some spacer material to add extra room for the additional neutral sections in the shift pattern. I think the shifter alone will take another month or two.

Edit: I just remembered one question I've wanted to ask...what size threads are on the output adaptor for the nv4500? I think mine has paint inside, so nothing I have easily threads in. They look like 5/16-18, but I'm afraid to torque the bolts in there if they are metric instead.
 
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clutch problems

Well, I got all the fluids in, new higher amp alternator with dual electric fans installed, motor all buttoned up, driveshafts installed and I am stumped at bleeding hydraulic clutch. After a long time bleeding, I can't seem to get any more than 1/2" of movement out of the clutch fork. It seems there's still air in there somewhere.

I'm also wondering if the clutch fork is adjusted properly for this bellhousing. It doesn't seem like there's a lot of room for the fork to move and I'm wondering if this is related to my problem. Check out this picture...
http://coloradok5.com/forums/attachment.php?attachmentid=52971&d=1188488627

This is about where it's at, although line is connected now. :) When the clutch pedal is up, the fork is about perpendicular to the tranny driveline. Some of the other advance adaptor bellhousing instructions for cars advice a forward angle on it, but this bellhousing "instruction manual" which only has one page in it shows it about like I have it.

Any tips? I've read through some posts about keeping the slave cylinder clamped together and that made a tiny difference, but not much. I'm bummed that I have to rent a J**P for blazerbash.
 
Have you verified the length of throw you are getting out of the slave compared to the spec?

Is the clutch binding & causing the slave to not extend fully?

I think I'd try to gravity bleed the clutch over a few hours. Just crack the line at the slave & periodically check the fluid level in the master, (like every 10 minutes). When the level drops, just add more. The fluid moving down through the system will cause the any air bubbles to migrate up throught the master. You just have to make sure the slave is full beforehand & not let the master get dry. If you do, you'll have to start over.

Worth a shot,
Buddy
 
I can verify that the clutch fork is not moving as much as it should. The clutch pedal travels almost halfway to the floor before any movement can be seen at the fork. I don't know if anything is binding, but I tried moving the clutch fork with my hands to disengage the clutch and I couldn't budge it any visible amount (maybe 1/8"). I can get more movement (~1/2") using the pedal.

One thing to note is that the fluid line I got came from the dealer for a late model truck so it's way longer than necessary. There's a spot where the fluid has to travel "uphill" before getting to the slave. Will gravity bleeding work ok in that situation? I tried removing the master and bleeding it in the air to make sure everything moved downhill, but not change.

The troubling part is the slave doesn't have a "real" bleed screw. It's just a set-screw with no nipple on it to attach a hose. So bleeding the slave involves spraying fluid all over the place and hoping most of it goes into a bucket underneath. (I'm looking for a compatible bleeder screw to replace it)
 
bp71k5 said:
I can verify that the clutch fork is not moving as much as it should. The clutch pedal travels almost halfway to the floor before any movement can be seen at the fork. I don't know if anything is binding, but I tried moving the clutch fork with my hands to disengage the clutch and I couldn't budge it any visible amount (maybe 1/8"). I can get more movement (~1/2") using the pedal.

One thing to note is that the fluid line I got came from the dealer for a late model truck so it's way longer than necessary. There's a spot where the fluid has to travel "uphill" before getting to the slave. Will gravity bleeding work ok in that situation? I tried removing the master and bleeding it in the air to make sure everything moved downhill, but not change.

The troubling part is the slave doesn't have a "real" bleed screw. It's just a set-screw with no nipple on it to attach a hose. So bleeding the slave involves spraying fluid all over the place and hoping most of it goes into a bucket underneath. (I'm looking for a compatible bleeder screw to replace it)
Click to expand...

I would almost guarantee that the "low-spot" is causing you're problems. It's causing air to get into the slave. Try to get the slave lower than any of the lines if you can. Even if you have to remove it from the bellhousing to bleed it.

Hope that helps,
Buddy
 
Yea that helps confirm what I suspected.

Although technically the slave is the lowest point already. It's just that the master is really too low so the hose travels upward a little before going down to the slave. Or is that just the same thing?

It's looking like that to do this right, I need to take it all out and bleed it as a unit and then put it all back. There's no way to do this with the master mounted where it's at.
 
I too fought my hydraulic clutch system alot to get it bled. The only way I was able to get mine done was with it off the truck. If I remember correctly I worked the slave pushrod alot to help get the air out - I sure wish I would have written down exactly what I did cause it was a bear of a problem. I did lots of searching here on this board to see what others did to bleed their system.
 
You can use a hand operated vacuum pump for bleeding. I can't remember the name of mine but I got it at Autozone for around 20 bucks. Just fill the reservior with fluid, find the right tip and put it down through the reservior to the line and put like 15" of vacuum on it, you'll be suprised how much air you get out. It took me several tries to get all the air out. Something else that will help is actuating the pedal with a vacuum on it.

Bill
 
mityvac

I think you can find these at pretty much any parts store these days as well, or even sears.

There is air in the hump that can't get out. I'd do what Yukon Jack recommended.

Good luck,
Buddy
 
I installed a Wilwood master cylinder and a Wilwood pull-type slave cylinder. I made sure to put the slave at the lowest point and had the bleeder screw facing up. A friend pumped the clutch pedal and then held it down while I opened and closed the bleeder. We repeated this process about ten times and the clutch has worked great ever since. Also, make sure you are getting enough stroke out of the master. There is a correct ratio to where the piston rod attaches to the pedal based on the length of the pedal. Not exactly sure but i think it is 3:1. As always measure 10 times before doing anything!
 
So I bled the system with the slave off so the lines all ran downhill. It's actually much better now, but not there yet. There may still be some air in there. I'm getting maybe 3/4" of slave movement from 1" of master movement.

One problem I now have is the fork is very close to bottoming out on the bellhousing. Advance Adaptors says I can clearance this out some to make room, but the fork alignment doesn't seem to be very great.

I'm thinking a longer throwout bearing might be a good way to go? I've got the shortest one in there right now and it looks like the next size up is 1/4" longer. This would make the fork align better inside the bellhousing and make me not have to grind the bellhousing. Any opinions on that?
 
Can't think of any real disavantages, and it may also give you a little more throw. I say try it!

Good Luck,
Buddy
 
Ok, so I took Buddy's advice and went to the parts store for a new bearing. It's always fun when they ask "What kind of car is it?". Then I explain it's a 71 blazer, with a 1967 327SBC, with a 1994 5-speed tranny mated to it using an AA after-market bellhousing. I have a favorite place that I've been in there so much they know me and are just as anxious as me to get the truck running again so they don't always ask anymore.

When I went to the dealer asking for a clutch hose with that information, he told me to pick one car or leave. :haha:

So I found two different release bearings which are supposedly the only ones used between 1967 and 1989. One is about 1/2" longer than the other. What's weird is that the one I installed is different than both of these. I can't remember what year/make info I gave them to get the original one. The one I installed has a plastic fork retainer groove and the new ones are much larger and are all metal. These seem to be better quality anyway.

Does anyone have any tips on what kind of release bearing needs to be used here? I'm pretty much stuck having to pull the entire drivetrain as an assembly out 6 inches to swap bearings. Lucklily once it's out I can make sure the clutch is working right before installing it again. I know it's gonna be heavy because everything is filled with fluid so I can't split them apart. (That includes $100 of the synthetic GM fluid for the nv4500!)
 
bp71k5 said:
Ok, so I took Buddy's advice and went to the parts store for a new bearing. It's always fun when they ask "What kind of car is it?". Then I explain it's a 71 blazer, with a 1967 327SBC, with a 1994 5-speed tranny mated to it using an AA after-market bellhousing. I have a favorite place that I've been in there so much they know me and are just as anxious as me to get the truck running again so they don't always ask anymore.

When I went to the dealer asking for a clutch hose with that information, he told me to pick one car or leave. :haha:

So I found two different release bearings which are supposedly the only ones used between 1967 and 1989. One is about 1/2" longer than the other. What's weird is that the one I installed is different than both of these. I can't remember what year/make info I gave them to get the original one. The one I installed has a plastic fork retainer groove and the new ones are much larger and are all metal. These seem to be better quality anyway.

Does anyone have any tips on what kind of release bearing needs to be used here? I'm pretty much stuck having to pull the entire drivetrain as an assembly out 6 inches to swap bearings. Lucklily once it's out I can make sure the clutch is working right before installing it again. I know it's gonna be heavy because everything is filled with fluid so I can't split them apart. (That includes $100 of the synthetic GM fluid for the nv4500!)
Click to expand...

Man, I hope it works! Sheesh, the pressure! :crazy:

Why not instead of trying to move the whole drivetrain back to (re)install the bearing, just pull the engine or loosen it up so you can get it back in there.

Just trying to help. Don't know if I am or not though.

Later,
Buddy
 
hehe, I'm open to any ideas!

I think I can rig something up to pull the tranny/case out a bit easier than I can pull the motor. Besides, if I pulled the motor, there'd be no way I could put it back in without "fixing" some of the things on it. :rolleyes: And you know how that goes.

In any case, pulling the tranny will let me leave the clutch hooked up and allow me to test it to make sure it releases properly before putting the tranny back in. A tranny/scissor jack might be handy for this. Yet another tool for the garage....
 
bp71k5 said:
hehe, I'm open to any ideas!

I think I can rig something up to pull the tranny/case out a bit easier than I can pull the motor. Besides, if I pulled the motor, there'd be no way I could put it back in without "fixing" some of the things on it. :rolleyes: And you know how that goes.
Click to expand...

You don't have to pull it all the way, just loosen it up so you can get in between there. Although I know the feeling. I need a new draglink, but I've noticed that the pitman arm shaft seal is leaking, so I might as well swap in a new box. But if I'm swapping in a new box I might as well do a 2WD box & add crossover steering too, but if I'm going to do that I might as well go ahead & swap in the D60, so I only have to buy one set of steering arms. But then I'll need 8-lug wheels & to swap out the rear 12-bolt to a 14-bolt. All for the need of a draglink. :doah:

bp71k5 said:
In any case, pulling the tranny will let me leave the clutch hooked up and allow me to test it to make sure it releases properly before putting the tranny back in. A tranny/scissor jack might be handy for this. Yet another tool for the garage....
Click to expand...

As long as you can get it done. You've always wanted a ATV jack anyways right? Right? :haha:

Later,
Buddy
 
Well I pulled the drivetrain out as one piece using a cheap ATV motorcycle jack and some wood 4x4 frame I made to support it properly. It came out in less than 30 minutes. I even switched throwout bearings and it looks like the longer one does fit better.

There's about 1/16" to 1/8" of clearance between the bearing and the clutch fingers. This other bearing allowed over 1/2". It also puts the fork in a much better position. It's weird because every application I looked at uses the smaller bearing, but they use an 11" clutch. I have a 12" installed.

It took a lot more work to get it back in, but finally did it. It's tough to manuever ~200+lbs of tranny+np203+np205+2 gallons of gear oil all at once to get the clutch shaft engaged.

I also fabbed up a shifter lever. One thing to watch out for is all the online links that list the thread size for the shifter list it as 14mm x 1.5 pitch. My tranny uses a 16mm x 1.5 threads. It took me a while to figure out why the 14mm fitting I bought didn't fit. I'll post pictures, but the shifter is just a straight piece of tube with a nut welded onto the end.
 
:whistle: waiting patiently for pics........

I could be doing something productive, but I'll just sit here & wait.

Later,
Buddy
 
Here's the new clutch fork position when released. Big difference.

Also the quick and dirty shifter for the tranny. The pipe fits right over the thread on the stub and I used a weld nut on the end. It feels kinda "light" so I may try some solid rod instead once everything is working and I see what length feels best during use.

clutchfork.jpg

stick.jpg
 
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