XJ Unit Bearing Bolts!!!!!

RAVC1 said:

Rats,

4 of the 6 bolts came loose without effort. The remaining 2 are challenging! Now I've used MAPP gas on both and I think this has degraded the bearing.

The first 4 were loosened with GM Heat Valve Spray (p/n 1052627) and it is excellent for these purposes. I just switched to PB Blaster to see if a little soak time with this will improve my luck in view of the positive comments people here have made about PB.

Any additional suggestions? Patience is always the difficult virtue!

Thanks,

Rick

Click to expand...

there are two things you can do to help the pb along.

afer you spray it onto to the area give the bolt a whack or two with a hammer or punch.

spray the pb on as it is cooling from the torch. the cooling will help suck it into the needed spots.

I seldom have trouble with the bolts themselves. try that with a 24 " breaker bar and you should do fine. then you are on to the MUCH more difficult task of removing the hubs themselves.

there is a very recent thread here about that.

can of pb blaster a big ratchet and an even bigger cheater bar, i used about a three and a half footer to bust them loose, throw a little anti-sieze on the bolts when they go back in, i bought an axle whare the previous owner used anti sieze and it made me go out and buy some, they still seat in good and tight but they wont be difficult to turn all the way out

Second the "whack with a punch" trick - it's worked well for me before.

If you can't get it loose any other way, you can still get it out, but it destroys the bolt (I think they've fairly long M8-1.0, but I haven't verified that yet. Replace with hex head capscrews or socket head capscrews...0:

Get a "pencil" flame torch - one with a VERY concentrated flame! You don't want overspill. Grab a candle or a block of canner's wax (paraffin wax) while you're about it.

Heat the threaded end of the screw to a dull red. Take away the torch, wait about two seconds, and touch the paraffin to the screw end. It will melt - the expansion of the screw will force the threaded bore open, the screw will contract, and wax will be wicked into the space created between the two. Do the other two, and go have a soda.

When you come back, the screws should break loose easily. Take them out, and throw them away (when you heated them to dull red, you also killed the heat-treatment, they've softened now. Use only for measuring replacements...)

I've done this a number of times - I originally learned it when I needed to break oil galley plugs loose on the back of engine blocks, and those were cheap and easy enough that we just threw them away out of hand.

Notes on never-seez - reduce installation torque by HALF if you use this stuff on threaded anything! I've nothing against it, but this is important - you can pull threads out if you don't follow this.

Installation torque on "clean, dry" for this is 75 pound-feet, if you use never-seez take it down to 37 pound-feet. If you want to use grease or oil on the threads instead, installation torque is 50 pound-feet.

5-90

ONe thing you should keep in mind, if the heads are getting a little sloppy, is that for a 13 mm head, you can get a bit tighter fit with a 1/2 inch socket. It may require a light tap with a hammer to seat down. That has saved me a couple of times. If the heat and penetrant don't do it, you may just have to bite the bullet and shear the bolts. I had this problem with my son's 96, which had apparently spend a good part of its youth by the Massachusetts seashore. Not a lot of body rust, but every bolt down under is concealing the most unusual kinds of rust. In his case, one of the bolts was totally seized, not at the thread, but along the shank where it passes through the knuckle. This is despite the fact that it's necked down to avoid exactly that problem. It was jammed solid with rust, and the only way I could get it off was to torch the ear off the hub itself, and even then I was unable to punch out the stub of the bolt, and had to burn it out bit by bit with a torch flame.

However, if it's just normal nasty rust, you can just try the big breaker bar and lots of torque and hope it doesn't shear. If it moves at all, then immediately stop, douse it with enormous quantities of penetrant of your choice, and then screw it back in. Continue this cycle, trying to increase the back-out movement a bit every time but not overdoing it, and you will not shear the bolt.