I bought a GM limited slip rear end for my stude project, thinking I would just move the spring perches. (never done this before) Now I'm getting educated and am told I need to gut the housing (easy on a ford - no clue on a GM). Then I need a jig (expensive) and a rosebud to preheat before welding, etc. or I'm going to warp the hell out of it? I can't do it right but don't want to screw it up. So is there a shadetree way that works? Can I leave it assembled, maybe clamp a big angle iron on the opposite side of the tube? The perches need to go out further, maybe 4 inches from the flange. They are 3/16 steel and only need about 3 inch welds. Of course, I don't have the money to just send it out. Am I screwed here?
There are probably hundreds of guys on here (including myself) who have welded spring perches onto a rear end without taking it apart. Unless it's a high-horsepower car a few good tack welds at each end of the perches are all you need. Give it time to cool between each one. If you want to get fancy you can also put tack welds on the opposite sides of the same tubes to (hypothetically) warp it back the same amount it warps in the first place. But unless you go gonzo with the welding it shouldn't distort too much in the first place. I have put around 10,000 miles on my car so far with no problems at all. It all measures out straight and true.
Absolutely not just becareful cutting them off too much heat cutting them off can warp the housing.You will need to buy new perches put them on the housing and weld them on with the axle in place on the car.
I used to cut them off with a torch very cleanly and re weld 'em on all the time. As said before, clean area well, stitch weld and do not over heat the area. Used to do Jeep rock crawling and definately stress tested them with big assed tires and lots of torque. never an issues
This is encouraging. Yes I have new perches. Can I just drain the fluid, or will the residue catch fire? Obviously I did not think this through.
A cutoff wheel on a 4 inch grinder will lay waste to the old ones. Tidy up with a flap wheel. Get ahold of some new perches, tractor supply has them in several sizes. Tack the new perches on, remember to set the correct pinion angle. Alternate welding, in different places, to avoid building up heat in any one area. Done.
Should be fine...a good weld is a good weld. I cut my old perches off, and welded the new ones onto my Versailles rear end in my '60 with it fully assembled... Also used a oxy/acetylene torch to remove them, then a flapper wheel to clean them up. No issues, no worries... Good luck... BRT
I don't think they took the rear end apart before moving the spring perches on my F*rd 8-inch for my Stude project.
That will be plenty good enough.If the new perches are located inside of the old ones I would not cut the old one off until after you install the new ones.They will help to locate the housing and also it would be easier to set the pinion angle.Just level the original perches and weld the new ones on after you bolt them down.
If you get the housing hot enough to ignite the oil on the inside then you have probably ruined the housing anyway. The big secret to removing and/or relocating brackets is to take your time. Cutting and welding a little at a time and then let it cool. Most damage is done when people continue to weld after the heat has built up in the housing causing warping. It can be hard to stop once you have a nice bead going. The urge to get it done is hard to resist. Move from one perch to the other. Weld a little. Walk away. Come back after you can touch the weld with your hand. Yeah it takes time but you don't get warped housings or internal fires. I've done a bunch over the years with no problems.
The 57 Chev rear I put in my 37 pickup never came apart before welding the pads on and it was still going 20 years later. The 55-7 Chev pads are tacked in 6 places on the housing from the factory instead of being completely welded (like the Fords are). Put it together, be careful about the heat on the tube, and it should be fine, assuming the housing isn't bent to start with.
Although I have never used them speedway makes bolt on spring perches for 3" axles. would make it alot easier to install and if you needed to you could probably weld them up after. Has anyone used them? Carlg
You guys make it sound as easy as I thought it was, untill I started asking questions. That's what I get for being on a "non HAMB" site. lol.
Now I'm getting educated and am told I need to gut the housing (easy on a ford - no clue on a GM). Then I need a jig (expensive) and a rosebud to preheat before welding, etc. or I'm going to warp the hell out of it? Lemme guess, the guy who told you this has a rear end rebuilding business right down the street and he wants to "save you" from screwing it up, but he'll be happy to do it for you if you pay him.
Cut sideways-into the weld, NOT INTO THE HOUSING. ...like my brother did...............still worked anyway.
Drill a series of in line 1/8 dia holes at the base of the old perches, being careful not to drill into the housing. Then take a chisel and cut them off. Grind down what left with a die grinder.
cut let cool cut let cool cut let cool then weld let cool weld let cool weld let cool thats the motto you need to go with
No, just because many have done it and had no warpage (BTW, did you check that there was no warpage or just assume cause the bearings didn't fry?) does not mean that is the right way to do it, it just means you had no issues that time yourself. I do narrow rear ends. I do have all types of jigs and a press to straighten, and usung a jig IS the RIGHT WAY to do it. Now with that said, on most rears on cars we build if it isn't getting narrowed or really built, I also just "cut and weld" with no jig. Have I ever had an issue? Just once. Will I do the next one the same way? You bet, but just because you and I get away with it MOST of the time, doesn't make it the "right way".
When its time to weld the new perches on make sure you put your ground clamp as close to the weld as possible. Right on the new perches if possible. DO NOT ground on the axle flange or the center section bolts as this might send the "ground path" directly through the bearings causing damage to them. I've seen this in industrial situations, not pretty! Good Luck.
I have done it two ways and both ways worked. The weld and cool method works fine, but I have also just nailed it with a real heavy hot bead, then gone on the opposite side of the housing and put another heavy, hot bead the same length. Axles still went in and out perfectly, showing there was no warpage. I do drain the housings, pull the axles, and hose them out with brake cleaner first. Just the clean them out.
If you want put cold wet rags on each side of the perch were your welding but I have done this many times not a problem
Your only screwed if you listen to them. Were Hot Roders, we do thing that you can't do. LOL Just do it, take your time, do a little weld, let it cool, do some more. I did mine completely assembled and you would never know it was a Chevy rear in the back of my 29 Pk Up. Iceman
I would arc it ,Unless you have a good mig check your pinion angle at the trans ,Opposite for rear and think safety have a hose or extinguisher near by ,Just in case . No need to take apart in my opinion
Just a follow up. Thanks to all the advice here, I got it done. Checked the tubes before and after, no issue at all. HAMB RULES
I know this isnt exactly the question asked. But i thought this might be helpful?To check a rearend or any axle assembly for straightness. Put rims on without tires place entire assembly in a H beam or large piece of chanell steel. If you have contact on four places on each wheel it is straight. To check your chanell or H beam use a string line. you can use heat or HYD pressure to straighten a bent or warped assembly. OldWolf
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