8.8 cross-pin bolts?

[MAKG]

OK, guys.

I got a rear end load-independent grumble, which I'm pretty sure is one of the bearings in back, probably an axle bearing. Regardless of which it is, the differential has to come out to inspect (pinions are nice and tight with it installed, so they are probably fine). 7.5's used to have a HUGE problem with breaking the cross-pin bolt on removal. Do 8.8s have a similar issue? What can be done to prevent breakage? What does one do if it DOES break?

 

[Ranger44]

When I was taking apart an explorer 8.8 the cross-pin bolt broke.

There are bolt extractors made for broken cross-pin bolts. There was a thread on here somewhere. A quick search brought up nothing for me though.

edit:

Think this is what they referred to:

http://www.etoolcart.com/differentialpinionshaftlockboltextractorkit.aspx

 

[4x4junkie]

Yeah, happens just the same on 8.8s.

I think the unthreaded part gets fatigued from the crosspin torquing against it, so when you go to take it out, it's often already broken.

 

[MAKG]

Can you get the cross-pin out with it broken, or do you get the oh-so-lovely task of drilling an installed carrier?

 

[rickcdewitt]

drill away with the one cap off,a reverse cut bit can sometimes make the bolt come out while drilling,too.heat on the carrier to cook the locktite has been used too. just make sure you use a 6 point 8mm so the bolt head doesn't strip.

 

[MAKG]

I'd be a bit concerned using a flame around all that gear oil. Is it a concern?

What's the geometry of this bolt and where it breaks? Is it a threaded bolt with a smooth extension to go through the cross pin and the other side of the carrier? It sounds like it breaks with threads on both sides of the break (otherwise the head would just fall off).

Who sells replacement bolts? Dorman?

 

[Evan]

I'd be a bit concerned using a flame around all that gear oil. Is it a concern?

What's the geometry of this bolt and where it breaks? Is it a threaded bolt with a smooth extension to go through the cross pin and the other side of the carrier? It sounds like it breaks with threads on both sides of the break (otherwise the head would just fall off).

Who sells replacement bolts? Dorman?

Correct, it breaks with threads on both sides. The bolt usually breaks off somewhere along the threads, leaving you with about a 1/4" stud in your hands.

On my first 8.8, the bolt was broken off. I ended up just buying a 1995 8.8 since I wanted discs anyway.

On the 95, I had to remove the bolt to install my locker. I cleaned as much gear oil away as possible using rags and brake parts cleaner. Then I heated up the carrier with a torch. I had a fire extinguisher at my side, but there were no fires. Gear oil doesn't seem to ignite too easily.

When you remove the bolt, avoid shock loads, like tapping the wrench with a hammer. Just get a good lever and apply consistent force until it breaks loose.

 

[Totalled]

Torch that sucker. It will release the locktite and it will unscrew like butter.. Gear oil takes a lot of flamage to catch, and if you wipe it off and hit it with some brake clean.. the most that will happen is a little stinky smoke.

 

[ForOffRoadDriving]

i broke one off in a 8.8 and was lucky enough to use a 90 pick to work it out. probably will never get that lucky again. the bolt started to come out and then snapped, so i broke the lock tite loose but then the bolt broke. it was about an 1/8 of an inch inside the carrier so i couldnt use pliers or anything. i went to ford and ordered 1 but they come 5 to a pack. the next day i went to work and was re-pricing my HELP! board and found out that i had the bolt in a single package. oh well, now ive got spares so ill just replace the bolt next time i have to take it apart again.

 

[4x4junkie]

Going just by memory...

The bolt is about 2½, maybe 3" long, with threads for about 1" directly under the head. The rest of it's length is a smooth pin that goes through the differential cross shaft.

I've also heard people being able to smack the cross shaft through using a huge punch and a sledgehammer after the bolt broke (shearing the bolt).

 

[metalmacguyver]

When trying to shear the bolt off, you must make sure that you drive on the bolt side of the crosspin. driving the other way, as to shear the pin and send it out the short way runs the severe risk of punching through the carrier.

I did it.

 

[rickcdewitt]

Is it a threaded bolt with a smooth extension to go through the cross pin and the other side of the carrier? YES
Who sells replacement bolts? Dorman?

parts house or the gear vendors

 

[Hahnsb2]

When trying to shear the bolt off, you must make sure that you drive on the bolt side of the crosspin. driving the other way, as to shear the pin and send it out the short way runs the severe risk of punching through the carrier.

I did it.

Good to know for future reference.

 

[Dan Rowe]

When I was taking apart an explorer 8.8 the cross-pin bolt broke.

There are bolt extractors made for broken cross-pin bolts. There was a thread on here somewhere. A quick search brought up nothing for me though.

edit:

Think this is what they referred to:

http://www.etoolcart.com/differentialpinionshaftlockboltextractorkit.aspx

Get the tool. These bolts break from fatigue (explained at www.fabbriassociates.com/kitinfo.html).

I got the extractor kit from www.etoolcart.com/differentialpinionshaftlockboltextractorkit.aspx at a better price. I've used it twice worked great no damage. Guide bolts are a huge plus.

 

[Evan]

FYI, this is the top part of the bolt I broke off in my old 8.8: