Working Man's Burbon

[HO455]

Sunday's project when like clock work for once. I replaced the rear trailing arm bushings. I used a lift as I am a cheater, but it can be done on jack stands without removing the trailing arms from the rear end. You have to have the truck high enough that the rear wheels are off the ground and room for a jack under the axle. Spray penetrating oil on the bolts and all around the bushings. This process is for replacing stock rubber bushings with stock rubber bushing
You need several things before starting. A 8" piece of All-thread 3/4" or 1/2" (3/4 is self-centering) with two nuts, several heavy washers, 1 1/2" diameter. ( Just under the diameter of the small end of the bushing) a piece of 2" ID thin wall tubing about 4" long, like exhaust pipe that will fit between the top and bottom flanges on the arm and still let the bushing pass through without touching, and a large washer or plate to go over the end of the tubing. A additional spacer to install the bushing is also needed. It must fit over the rubber on the lipped end of the bushing and be able to press on the lip to push the bushing into the arm. These pieces make up the bushing removal/ installation tool. If you have the new bushings it is pretty easy to find the correct sizes. You will also need a spacer three inches square by one inch or equivalent to hold the arm in place while you work on it. Two wrenchs one for each of the nuts on the bushing tool, two large wrenches for the trailing arm bolts, a 5 foot long 2x4, a wire brush, a propane torch, and penetrating oil is all that is needed.
Once you have the truck securely on the jack stands use a wire brush to clean all around the bushings. If you have a lot of rust then some Emory cloth should help to clean up the center area of the bushing. Spray with penetrating oil. Then remove one of the bolts that hold the front of the arm. 1 1/8" wrenches are what I needed. There was very little pressure on my arm at this point and by jacking the axle up about 1/2" the bolt was free and I pulled it out by wiggling the trailing arm. The next step is to get the arm to drop down below the tabs that hold it to the cross member. By jacking the axle up and pushing back you can get the arm to clear the mount. (I know it seems odd but jacking the rear end up makes the arm drop up to a point then it's all armstrong.) It will be harder to get it to drop farther but it is necessary. I used a 5 foot long 2x4 over the arm and under the frame rail and pulled the arm down and put the bolt back in place above the arm. The 3x3 spacer is now used to go between the top of the arm and the bottom of the bolt. (Photo 1 shows what you need to achieve. I should have found a more photogenic spacer ) This next step is much easier with help. Pull the arm down with the 2x4 again and insert your spacer(s). If you don't have help a bottle jack and a piece of 3/4" plywood to protect the floor board should work too.
Once in place you have to assemble the bushing tool. (You may want to hit it with the wire brush and oil again now the bolt is out of the way.) All thread goes through the bushing. The tubing goes over the larger end of the bushing without touching the bushing. (On my Burban the large end was on the drivers side.). The big washer over the end of the tubing. The smaller washers go on the other side centered on the bushing. (Photo 2 shows order of pieces. Photo 3 installed.). Once everything is in place put some lube on the All thread and install the nuts. After double checking that the tubing is clear and the washer centered slowly tighten the nuts. The small end with the washer will want to shift around so you may have to take a piece of wood and a hammer to recenter it. The rubber on that end will push over and try to jam things up. (Photo 4) I just took a scraper and peeled it off as it happened. Once you have things snugged up (not knuckle busting tight) take the torch and heat the area on the rail that surrounds the bushing. No need to get it red hot just hot enough so your spit sizzles when you spit on it. You just want the holes the bushing goes through to slightly expand from the heat. Then spray some penetrating oil on the bushing between the rails. This lubes the bushing and helps cool it so it contracts slightly making it easier to get out. Then tighten the nuts some more and the bushing should push right out. Pay attention to make sure the bushing is moving and you are not deforming the arm. Particularly stubborn bushings may require you cool and reheat the arm to get it to break free. This method will remove 90% of the bushings out there. If you a 10%-er then more drastic means will be required. It only has to move about a quarter inch and it is free, so sawsalls are an option as would be removing the trailing arm and using a press.. (Sawsalls aren't necessarily the one I recommend.) Once it is out take your wire brush and clean the area around the bushing.

[HO455]

Bushing installation is the reverse process. Set up your tool so the tubing is on the side that is pulling the bushing. I forgot to mention that the installation spacer on the lipped end of the bushing will need to have a large washer over it also. (Photo 1). Once you have the tool organized and ready to go set it some where close and then reheat the trailing arm again. In the area around the bushing. Once again no need to make it glow red. Just hot enough to make your spit sizzle. That's in the 250 degree range. Then slide the bushing in and assembly the tool and tighten the nuts. Watch carefully that the bushing starts in straight. If not stop and remove it. You can always cool the bushing in water and reheat the arm. Once the lip side is seated all the way remove the tool and pop yourself a cool one because you deserve it and it makes waiting for things to cool off easier. After everything is cool to the touch reverse the process. Remove the spacer(s) by pushing the arm down. Clean up the bolt and nut and reinstall. Repeat on the other arm. Then sit back and savor that sweet Suburban goodness you just created.

[HO455]

More "oh by the way's). When I left off on the caster modification I had not installed the shocks due to the local supplier being unable to provide the right ones on the first four tries. Now that I had the correct ones I realized that when the bags were aired out the shocks would hit the cross member or the brake line bracket. The easiest option was to fabricate new mounts and repostion the lower shock mount on the arm. I took heavy wall 4" x 2" square tubing and cut one end off to make a U-shaped shock mount. Then trimmed it to shape and drilled a 1/2" hole (photo 1). The small notch allows the mount to fit onto the rolled edge of the control arm. The old mount was cut off and then after many up and down checks I found the right location. A quick clean up with a grinder to remove the paint I just put on. I tacked the mount on the arm and ran it up and down once more to confirm before welding it out. The difference in location will affect how the shocks feel inside the truck as they are now closer to the frame and more vertical than before. I apologize about the poor photos. But the last photo shows how much room there is now. I'm not a big fan of those red boots, but they did give me a smoke'n deal on these Rancho 5120's for all the time and trouble they caused. Plus hopefully I won't have to look at them again for a couple of months.

[crakarjax]

Looks good! I am using SS7 bags as well and also noticed some separation at the top plate -- I'm hoping this is by design because my bags were sitting on the shelf for a couple of years.

[Dieselwrencher]

More nice work on it!

[HO455]

Originally Posted by crakarjax

Looks good! I am using SS7 bags as well and also noticed some separation at the top plate -- I'm hoping this is by design because my bags were sitting on the shelf for a couple of years.

Thanks. I would call Slam and ask, they have been patient with all my questions.
Good luck.

[HO455]

Originally Posted by Dieselwrencher

More nice work on it!

Once again thanks!

This morning I wanted to put the mirrors back on the Burban. I stood and stared at them for a while in order to find a way to get the plates in position without removing the door panels. (They fell to the bottom of the doors when I removed the mirrors) Here's what I came up with. First I ran two wires (string would work too) down from the outside staying clear of the window regulator and out of the speaker hole. (This is where cut door owners win out. ) after making sure they were not crossed, I ran the wires through the plate. One of the wires I pulled extra long and then tied the two together to make a wye. ( or a Y ). Before pulling the plate up I put the gasket in place with the wires through the outer holes. I then used the two wires to pull the plate up past the regulator and nearly into position. Using a 90* pick I moved the plate so I could start a stud in the middle hole. Once I had the stud installed I removed the wires. This is where the longer wire in the wye came in to play. No need to try and get my hand up there to pull them out. Holding the plate by the stud I put an extra long bolt through the front hole in the mirror, gasket and plate. Then fit the mirror in place and installed the back screw. Then one at a time I replaced the stud and the bolt with the proper screws. Once everything looked proper I pulled the screws and put some blue Loctite on them.

[Hart_Rod]

Originally Posted by HO455

Once again thanks!

This morning I wanted to put the mirrors back on the Burban. I stood and stared at them for a while in order to find a way to get the plates in position without removing the door panels. (They fell to the bottom of the doors when I removed the mirrors) Here's what I came up with. First I ran two wires (string would work too) down from the outside staying clear of the window regulator and out of the speaker hole. (This is where cut door owners win out. ) after making sure they were not crossed, I ran the wires through the plate. One of the wires I pulled extra long and then tied the two together to make a wye. ( or a Y ). Before pulling the plate up I put the gasket in place with the wires through the outer holes. I then used the two wires to pull the plate up past the regulator and nearly into position. Using a 90* pick I moved the plate so I could start a stud in the middle hole. Once I had the stud installed I removed the wires. This is where the longer wire in the wye came in to play. No need to try and get my hand up there to pull them out. Holding the plate by the stud I put an extra long bolt through the front hole in the mirror, gasket and plate. Then fit the mirror in place and installed the back screw. Then one at a time I replaced the stud and the bolt with the proper screws. Once everything looked proper I pulled the screws and put some blue Loctite on them.

Very creative! I just used some 2-sided tap to stick the backing plates to the inside of the door...

[HO455]

So the rest of the story is, 15 minutes after I finished this I saw the tube of caulking in the back of the WMB and thought " Dang, I should have put some on the plates" and then never had to do this again. Oh well, I never claimed to be a genius.

[Hart_Rod]

Originally Posted by HO455

So the rest of the story is, 15 minutes after I finished this I saw the tube of caulking in the back of the WMB and thought " Dang, I should have put some on the plates" and then never had to do this again. Oh well, I never claimed to be a genius.

[HO455]

I got up on the alignment rack again today. The first photo is from Friday of the starting point. I certainly got lots of caster! More than I wanted. I started with the existing shim packs with one exception. Instead of a 3/4" or more stack of shims I made some 3/8" and 5/16" spacers to reduce the number of shims. After much back and forth I got things pretty close to the specifications provided by BMERDOC in his alignment thread. (Photo2)
http://67-72chevytrucks.com/vboard/s...=487363&page=9

I came to the realization that the air bags really affect your camber settings. I picked a ride height but I may go with a higher one as I think I have right camber but i am out of room on the bolts. By going with a higher ride height that should allow me to reduce the number of shims instead of having to install longer bolts to hold the control arms on. Photos 3 & 4 show the shims and bolts. The last photo is the rear axle readings which show my need for an adjustable panhard bar. With the lowered rear suspension it is pushing the rear end to the passenger side and as a result it no longer perfectly in alignment with the frame but it is -.10 degrees off of center line. It actually is better than I expected it to be. I bet if I were to replace the bushings it would get worse. Sometimes old and worn out is your friend.

[notchbackgta]

I don't think that much castor is going to hurt anything, just make the steering feel a little heavier. I wish the steering wasn't as light in these trucks honestly. I think Mercedes run even more than your initial, they run like 12 or 15, something crazy high.

[Hart_Rod]

Originally Posted by HO455

I got up on the alignment rack again today. The first photo is from Friday of the starting point. I certainly got lots of caster! More than I wanted. I started with the existing shim packs with one exception. Instead of a 3/4" or more stack of shims I made some 3/8" and 5/16" spacers to reduce the number of shims. After much back and forth I got things pretty close to the specifications provided by BMERDOC in his alignment thread. (Photo2)
http://67-72chevytrucks.com/vboard/s...=487363&page=9

I came to the realization that the air bags really affect your camber settings. I picked a ride height but I may go with a higher one as I think I have right camber but i am out of room on the bolts. By going with a higher ride height that should allow me to reduce the number of shims instead of having to install longer bolts to hold the control arms on. Photos 3 & 4 show the shims and bolts. The last photo is the rear axle readings which show my need for an adjustable panhard bar. With the lowered rear suspension it is pushing the rear end to the passenger side and as a result it no longer perfectly in alignment with the frame but it is -.10 degrees off of center line. It actually is better than I expected it to be. I bet if I were to replace the bushings it would get worse. Sometimes old and worn out is your friend.

You could always go with a longer aftermarket upper control arm.

[HO455]

Great

Originally Posted by Hart_Rod

You could always go with a longer aftermarket upper control arm.

Thanks for that information. I didn't know they made them that way. I think I will put some miles on it and then decide the next step. That way if there is any other issues I can address them too. One thing is for sure I'm not thrilled about the way the nuts are on the control arm bolts. Earlier today I was contemplating pulling a shim off each bolt and then raise the ride height to get back to .010 camber. It may be a 3/4" or a 2" gain in height I don't know. It might just turn out to be an exercise in education and not actually get me anywhere.

[crakarjax]

You could just use an offset control arm crossshaft http://www.rockauto.com/en/moreinfo.php?pk=202859&jsn=3

[HO455]

I didn't think they made those for the solid bushing control arm shafts.

[crakarjax]

Originally Posted by HO455

I didn't think they made those for the solid bushing control arm shafts.

Ah I didn't think about that -- they don't seem to make one I guess. I guess I'll run into this same issue... a couple of ideas:

- Taller upper ball joint to swing the arm out away from the engine a bit (depends on arm placement at ride height)
- Longer cross shaft bolts and extra solid spacers
- Slice the control arm near the bj and weld back together, adding some material

The last option would allow you to correct the ball joint angle at the same time by taking a pie-slice out of the sides of the control arm. I don't recall anyone with a drop requiring any of this though (besides bj angle).

[HO455]

Originally Posted by notchbackgta

I don't think that much castor is going to hurt anything, just make the steering feel a little heavier. I wish the steering wasn't as light in these trucks honestly. I think Mercedes run even more than your initial, they run like 12 or 15, something crazy high.

Somehow I missed your post and I apologize. I was shooting for 5-6 degrees of caster and ended up only slightly off of that. I was surprised by having 9 plus degrees to start. The reasoning behind my feelings of having too much is if I had had 5-6 degrees to start I would have needed fewer shims on the rear bolts and then the nuts would have full thread contact and I would feel better about it. Come to tink of it that may be another solution to the problem. I could pull the lowers and redrill the shafts closer to stock and lose those shims. No shortage of things to ponder.
Thanks for the insights.

[HO455]

I replaced the rear bags today. I went with Slam SS-7's like I have on the front. The mounts were different between them and the old ones so a new plan was needed. Which was fine as the old bags were bolted to the top spacer and then the spacer was welded to the frame. Which has seemed to work ok up to now but it left no easy way to remove the bags. (Photo 1) I had to take a rotary die grinder with a carbide cutter and remove about a 1/2" of material on each side of the air fitting in order to fit a wrench in and remove the fitting. Once I had the fitting out I was able to remove the nuts from the studs holding the top of the old air bags. Then I removed the bottom bolt and tossed the bags aside. Then I removed the two tabs up inside the spacer that secured the bag with a pair of Vice Grips. They were only welded on one side so they broke right off. After some clean up with a 4" grinder I noticed that the bottoms of the spacers were not cut off square. (Photo 2). Another 15 minutes of grinding got them fairly square.
I had cut two six inch circles of 1/4" plate for the new bags to bolt to. Marked the center of the plate, scribed a line through it and then center punched two spots 1 3/8" from the center for the mounting bolts. These got drilled to 19/32". Then I scribed a second line 90 degrees to the first on the center of the plate. Then center punched a spot at 1 1/4" from the center and drilled it with a 1 1/8" hole saw for the fitting to pass through. Using one of the old front mounts as a jig I welded four tabs on each plate. Some clean up grinding then a quick shot of paint. (Photo 3). After carefully test fitting the plates I locked them in place with an air jack then center punched all the holes in the tabs.
I planned to drill and tap the upper mount to hold the plates. Over the years the best way I have found to tap things like this is with a cordless drill. As long as you have room for it. (Photo 4 Just barely room) First off you must have a sharp tap to do it this way. Then make sure you have drillled the correct size hole for you tap. The trick is to put the drill in the slowest speed and then set the setting dial to screw and not drill. Then put the clutch in a middle setting. Before starting put cutting fluid (most oils will work OK) in the hole and on the tap. Start the tap in the hole slowly making sure you keep the tap in the same plane as the hole you drilled. The nice part of using the drill with the clutch is it will stop the bit if your at a bad angle and you can then reverse and start again. By changing directions often you keep the chips from binding the tap and it becomes somewhat self aligning. After each hole clean all the metal chips off the tap and reoil for the next hole.

[Advanced Design]

Just catching up. Really nice work!

[HO455]

Thanks Doug. I forgot to mention it was 67-72 day at the shop.

[HO455]

Now all the prep work is done it's time to bolt it all together. Install the fittings in the bags, bolt the plates to the bags, bolt the plates to the truck. When I put plate and bag in position I just installed one bolt and left it loose while I inserted an 7" headless bolt through the trailing arm and threaded it into the bottom of the bag as a guide (You can see it at the bottom of the 4th photo. You could use a longer regular bolt, but I didn't have any handy) Now I installed and lightly snugged up the rest of the bolts that hold the plates. After hooking the air lines back up I slowly inflated the bags until they were just touching the trailing arm. This allowed me to adjust the bottom of the bag with a rubber mallet until I could untread the bottom bolt I had used as a guide and then install the correct bolt. Once every thing was done and the truck on the ground I crawled under and tightened the bolts that secure the plates in position knowing that any play between the plates and the spacers had been removed by the weight of the truck. The last picture shows one of the old bags and the split in the outer layer of the rubber at the top of the bag. They didn't leak, but I am sure it was just a matter of time. I inspected the aluminum top plates of the old bags thinking I would find some kind of wear pattern from the unevenness of the spacers they were bolted to. To my surprise there was none. I guess the bags must of prevented shocks hard enough to do damage.

[HO455]

Spent some more time on alignment Monday. Went over to Trackside Motorsports and we went over it again. They have a nicer set up with wheel plates. So much easier! After it was all said and done I went with a one inch higher ride height and that made it possible to lose three shims on each side and now the nuts have full thread contact and the camber is not as aggressive. I will drive it for awhile and see how I like it. The other thing we looked at was bump steer. With it still on the rack I raised it up and dropped it and we checked the toe numbers. With the air bags full and suspension at max drop the toe changed 2* and with it aired out it was a .08 degree difference. Which the guys at Trackside said was real good. They are Rally racers and are happy with 7-8 degrees with a much larger suspension range of movement. After finishing there I was off to the muffler shop. I have in the past done my own exhaust pipes but I sold an old video game and had some extra cash. It was nice to drop it off and pick it up the next day good to go. The I went for a 45 mile shake down run around town. Some highway, some stop and go rush hour, and a nice cruise up Skyline and back. The only issue is the speedometer cable is now making a huge racket. They must have repositioned it some how.
I do like the way it drives but the rear shocks are lacking. I haven't done anything with them yet and who knows how old they are in addition to they are at the bad angle that comes from lowering. Yet another thing to tend to. Tomorrow back up on the lift to check every bolt one more time for peace of mind.

[francisharvey]

This is a good one. Very good reference for others who are having the same experience. Thank you.
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Carpet Cleaning Annapolis

[Ol Blue K20]

I've been watching but haven't said anything lately. It's looking awesome and good luck with figuring the best ride height / alignment. Keep up the great work.