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91 Burban build thread

Two sided to every story

So, I worked most of the day Saturday pulling out the old 10 bolt from the rear. It took a while cause I wanted to get the e-brake lines out and the drums were seized on the lugs. So, I had to open the diff and pull the C-clips out to get them out of the way. I've never done that so it was a bit of a learning experience. Its funny that I've read everything I can about 14 bolts and 60s and I have no clue about the axles that were in my truck.

So any way, at the end of it all, I was loosening the U-bolts that had lots of gunk on the thread so it was a real bitch. I didn't have a deep enough socket so I had to do it with a wrench for the first several turns. Any way, after much cussing, the axle finally dropped out with a thud.
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Immediately, I hear my son say "I did it Daddy". He was absolutely convinced that he got the axle out.
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His story is that he put that tool in the hole and it came out. Just by coincidence, it had fallen out just after he stuck the pipe wrench in the receiver and clanged it around. He's a good helper!

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master Cylinder

So, I haven't even tried it yet but one thing I never hear about is what you guys do with your master cylinder when you swap in the 1 tons. I've got the Master Cylinder out of the donor CUCV (See Exhibit A)

Exhibit A
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You can see the massive rear reservoir most likely there to supply fluid to the massive drums on the 14 bolt (See exhibit B)

Exhibit B
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So, those rear brakes are so big because they are for a 1 ton truck that carries a lot of weight in the back or on a hitch. (there was this cool little proportioning valve that was actually adjusted by the rear axle height. As the springs compressed, the valve was actuated by an arm extending from the axle)

So, I may carry a light load or even haul a small trailer but I can't imagine
using those brakes to their capacity. Also, I'm sure I'll make the switch to rear disk eventually. Then what in the world will I do?

So the question is, do I keep the current master cylinder or put in the donor from the CUCV?

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Yea, I didn't keep that valve thing. It stayed on the CUCV and went tho the scrap yard. What about the Master Cylinder?
 
I have the same 1 ton brakes on my '90 Sub and kept the stock 1/2 ton m/c with no issues at all.
 
This is a good question that I believe ends up being personal preference. I would say yes to using the CUCV MC because it was designed to be used with those brakes. The catch is that the hydroboost may complicate a hydraulic assist type of steering set-up that you may want to put in down the road. If you are ok with your steering the way it is, go with the CUCV set-up. If you are looking into hydraulic assist steering, you way want to explore other avenues.

FWIW - I bypassed the load valve on the rear brakes and it worked fine. With bigger tires, more brake pressure is a good thing.
 
This is a good question that I believe ends up being personal preference. I would say yes to using the CUCV MC because it was designed to be used with those brakes. The catch is that the hydroboost may complicate a hydraulic assist type of steering set-up that you may want to put in down the road. If you are ok with your steering the way it is, go with the CUCV set-up. If you are looking into hydraulic assist steering, you way want to explore other avenues.

FWIW - I bypassed the load valve on the rear brakes and it worked fine. With bigger tires, more brake pressure is a good thing.

Well, Its a diesel so I've got hydro boost brakes already and my steering box is tapped for hydro assist. I haven't installed the ram yet but that is coming soon. What do you think?
 
Well, Its a diesel so I've got hydro boost brakes already and my steering box is tapped for hydro assist. I haven't installed the ram yet but that is coming soon. What do you think?


Try it and see how it works. That may make the decision for you.
 
be careful with the hydroboost, more braking power (bigger MC)+ ram assist can cause a loss of steering when you brake. if your going that route (which i agree with) get your hydroboost bored out for higher flow, which would probably make your steering and braking power much better than stock.
 
I positioned the rear axle today. Its been in place for a week now but today I was taking measurements and adjusting it to get it positioned just right. Its a lot trickier than I thought it might be.

First of all, moving a 500 lb axle that is loosely clamped to leaf springs is no small chore. Complicating the process is that fact that the leafs will move laterally with the axle when I make the small adjustments. So, it was a lot of moving and measuring and moving again. I'll take all your suggestions on that.

The other part is setting the pinion angle. I just bolted up the old drive shaft and centered it by comparing measurements from the yoke straps to a common point on the side of the shaft. I'm not sure I'm explaining it well but it was pretty easy. I set the pinion about 1 degree low. Here's why. the shaft i have now is too short so the position of the U-joint at the slip yoke is about two inches too far out. Also, I'm trying to anticipate axle wrap under normal driving conditions. I think those two things combined will keep the pinion withing 1 degree of the shaft. I'm going to call Tom Wood tomorrow and order it.
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the angle on the shaft isnt as big a deal as the angle on the joints

If you are are referring to the pictures, I was just finding the angles for reference. I'm sure its not a big deal but it will be handy to know the angle my shaft is running at. You are right though, its the angle at the pinion that I'm trying to perfect.
 
I ordered my rear drive shaft today. It should be in next Tuesday. Tom Wood is a pretty cool guy to deal with. I'll show pics when it gets here. I need to get a new front drive shaft but that will have to wait a little while.
 
When I measured mine I jacked it all the way up and then let it down and the length of the shaft didn't move much was very suprised but it made sense with the shackels.
 
Long overdue update.

So, its at about 90%. I've been driving it to work and on errands just to "work out the kinks". So I'll try to list the things I've done to this point

Front D60 swap to include:
new springs and bushings for the king pins. I shimmed the passenger side with a fender washer to help with the death wobble.

Cross over steering with a 4 inch drop pitman arm. I had the steering box rebuild and the sector shaft changed and it was also tapped for the hydro assist. As a part of that, I removed the sway bar and I've never even thought about it.

I haven't put the hydro ram in place yet. here's why. The passenger side is actually lagging behind the driver side by about 1/4 inch. I think this is causing the rig to pull the right and also exacerbating the death wobble. I can't figure out if my frame is tweaked or my spring pins are not exactly the same distance from the front hanger. Its very minor and I'm not sure I want to fix it. Once I decide what to do, I'll mount the ram.

The rear axle was pretty simple, I was just waiting on my welder for a while. Once I got it in place and the perches tack welded, I pulled it out, completed the welds, welded the shock tabs, cleaned and painted it. I did put on new brake lines.

The new drive shaft was so easy to install its not worth writing about. Here are all the pics.

You guys let me know if you have any ideas about he front axle being out of square.
Oh yeah, the surplus H1 tires I got are pretty square. I guess they are trying to make up for my front axle. I'm thinking about some SSRs. I would like to have a long lasting tire on a 16.5 rim. I really wish the new BFG K2 muds came in 37x12.5x16.5
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