1991 Diesel (conversion) Suburban

[chilliwak]

Nice work you have done Jj,:Wow1: but I am a little curious as to your front spring set up. First did you go with a 2 inch lift, and are the springs rated for a 3/4 ton? As far as I can see you have a 4 leaf pack, and the poly bushings stick out a fair bit from the leaf pack. Were they later compressed so that they are aprx. the same width as the spring? Curious because I will probably be doing the same work to my truck this summer. Keep up the good work and the truck looks great!

 

[jjosu]

They're 4" and I believe rated for 2500's, though I ordered them so long ago I really kind of have forgotten. Either way, they were a temporary fix. I'll eventually go with Tuff Country's or customs at some point. The poly's are as you noted - they stick out a fair bit and are flush with the spring mount and shackles. I assume that's the way they're supposed to be since they are Superlift bushings for that particular leaf spring.

 

[warwgn]

One final thing for the night (I think?) A decision has been made on the TCM/wiring issue. Thanks to some advice from thedieselplace forums, I'm going with an aftermarket, standalone TCI/TCU.

I have a brand new in the box TCI internal harness for a 4L80E if you find you need it, and I also have the remote TPS sensor hook up. Dont know if you need either but if you do hit me up.

 

[jjosu]

warwgn, stock TCM or aftermarket TCI? Either way, I'd be interested as I haven't ordered anything just yet.

 

[warwgn]

I dont have the controler I already sold that, I just have the upgrade harness that goes inside the transmission. If you have fresh rebuild you prolly dont need it. The remote TPS is used if yor engine does not have a hook up for one already.

 

[chilliwak]

They're 4" and I believe rated for 2500's, though I ordered them so long ago I really kind of have forgotten. Either way, they were a temporary fix. I'll eventually go with Tuff Country's or customs at some point. The poly's are as you noted - they stick out a fair bit and are flush with the spring mount and shackles. I assume that's the way they're supposed to be since they are Superlift bushings for that particular leaf spring.

Interesting that the bushings stick out so far in a stock Superlift set-up. I will be interested to hear how they last after you put some miles on them. Also, am I correct in amusing that the springs are a 4 pack, as in 4 leafs to each spring? I am driving a half ton and its a 5 pack. Let me know about your set-up. Cheers, Chilli.

 

[jjosu]

Not a whole lot done today. Extended brake lines installed and rear shackle flip started. Man, those rivets are a PITA to get off. Fuel sending unit came in on Saturday. Probably won't do a lot there until the rear suspension work is complete, since the tank pretty much has to be out for that process.

 

[chilliwak]

Keep on giving her the old elbow grease.:Wow1: I am sure those rivets will come off eventually....

 

[jjosu]

Here is the secret to rear shackle rivets that we learned yesterday and today.

Step 1 - Use a cutting wheel to notch the shackle-side rivet heads in several places. A cross might work. The key is to go deep, all the way to the shackle metal.

Step 2 - Air chisel the heads off.

Step 3 - Use air chisel or a HD pry bar and work the shackle loose from the frame. I suspect it's easier to do with the leaf detached, but we didn't do that.

Step 4 - Once the factory shackles are loose on both sides, lower the axle far enough for clearance.

Step 5 - Grind the shackle-side rivet studs flush with the frame. FLUSH IS THE KEY. Tried the air hammer when they were sorta close to flush and it wouldn't go. Got flush and...

Step 6 - Air hammer those puppies out. If you got the studs flush to the frame, the air hammer should pop each one in 10 seconds. I didn't use a hammer and punch, but imagine it would work at this point if you don't have air hammer/chisel.

Pics coming in a bit. Passenger side of rear suspension is DONE. Even but a wheel/tire on there. Driver side still needs the shackle flip mount installed. The leaf bushing on that side has seized the bolt. Nut came off easy, but the bolt took rust breaker, a BFH and propane torch to come loose. I was going to replace all the rear leaf bushings later, but that one now needs replaced (with a poly).

 

[jjosu]

One BFG KM2 35x12.50x15 mounted on ProComp 15x10's, mounted on the Burb! Sorry, did not get any good pics of the shackle flip.

 

[jjosu]

A lot done this morning. Suspension work is 90% done. Just have to mount all the front shocks. Steering arm final gave up the ghost on the cone washers and has been replaced with the raised version. Front wheels, despite just 2.5" of backspacing rub just a tiny bit on the calipers. Grinder time this afternoon!

Stopped at NAPA this morning to pick up a brake line and checked on my torque converter. I guess it arrived this morning! Big deal because nothing was going to happen on installing the 6.5 until the TC was in. Goal for this afternoon is to be able to put on the wheels, lower it down and move it over from the lift stall. Had a hunting trip to South Texas planned for this weekend, but it looks like we're going to be a few days long on having the Burb ready to go. Darn it.

 

[jjosu]

Did some paint work on the hubs this afternoon, popped the rear diff cover to figure out what gear ratio I have (haven't done that part yet)...man, the stuff that came out looked like chocolate sauce. Hit the front calipers with a grinder, put the wheels and tires on and lowered it to the ground for the first time with its new look. Here's the pics.









Roughly 5" of lift in the back, 4" in front. Front currently sits a little higher, but that's to be expected with 900 lbs not up there.

 

[jjosu]

Got a ton done today, or at least it feels like it. Buttoned up the final touches on the suspension and got it off the lift. Drained the fuel tank, replaced the sending unit with a new diesel version. Took off the gasser fuel filter on the frame and blew out all the lines with compressed air. Also popped the rear diff cover. The burb has 4.10's. Cleaned her upand re-filled with 80w90. Here's what's left:

Re-install fuel tank
Replace torque converter
Install standalone TCU for the 4L80e
Remove unneeded wiring harnesses
Order/fab left hand battery tray
Install engine
Pray

 

[jjosu]

I dont have the controler I already sold that, I just have the upgrade harness that goes inside the transmission. If you have fresh rebuild you prolly dont need it. The remote TPS is used if yor engine does not have a hook up for one already.

Finally figured out what you meant here and I may well need the internal harness. My tranny is a Goodwrench Reman of unknown age/mileage. The EZ-TCU does require an upgrade to the internal harness. Not 100% sure, but pretty close to that that I will need the internal. What do you want for yours?

 

[jjosu]

TCU arrived today. As noted in the above response, it requires an upgrade to the internal harness. No idea if my tranny has it or not. Guessing probably not.

Started to re-install the tank with the new sending unit, but got thrown for a loop in noting that the gasser sending unit has 4 in/outlets and the diesel only has 3. It was pretty apparent that the missing one was the vent. We knew the tank has to vent or will collapse due to pressure, but had a hard time solving it. Asking around a bit and using a small bit of intuition, the answer was...the gas cap. Need a new, vented gas cap and we're good to go.