Diff Mount Bolts Stuck

[Keith M.]

They have yet to cooperate. Been hitting them for days with PB Blaster. My next step is to get some plain (non castle) nuts that match the castle nut size and use said nuts as like a spindle knocker....carefully so as not to strip threads. My only other idea is apply some heat. I just want to confirm that these bolts are not threaded into anything insite of there so they can/should knock straight out. I did put a breaker bar on the bolt heads a few days ago but no love. anywho...thoughts?
Thanks,
Keith

[Patrick H.]

Re: Diff Mount Bolts Stuck

Correct, they are not threaded into anything and should be able to be removed.
It the unit out of the car?

[Keith M.]

Re: Diff Mount Bolts Stuck

Diff is out of car and detached from crossmember.

[Joe L.]

Re: Diff Mount Bolts Stuck

Diff is out of car and detached from crossmember.

Keith------


The reinforcing plate shows significant corrosion damage.

[Larry E.]

Re: Diff Mount Bolts Stuck

Keith: I would try CRC Freeze Off. It has worked for me where nothing else
helped. JMHO>Larry

[Keith M.]

Re: Diff Mount Bolts Stuck

Keith------


The reinforcing plate shows significant corrosion damage.

Hi Joe,
Hmmm...prolly looks worse in the photo than in person. I will keep an eye on it but til now I only see surface issues and it would appear to have adequate integrity. Once I get it cleaned up and Evaporust should be able to have a better sense. Thank you for calling my attention to this.
Keith

[Keith M.]

Re: Diff Mount Bolts Stuck

Keith: I would try CRC Freeze Off. It has worked for me where nothing else
helped. JHMO>Larry

Thanks Larry. That is a new product for me and will give it a go. Last night I did get some 7/16-20 nuts..put one on then held an impact socket over it and a few swift blows with a BFH. No love. This is after a solid week of PB blasting. I have also tried a breaker bar on the bolt head but am only going so far by feel as I want to avoid snapping the head off. Hoping with patience and continuing this regimen she will go. The hammer raps should shock the rust free...at some point. Will try and grab a can of this today.

[Gary C.]

Re: Diff Mount Bolts Stuck

Keith,

CRC Freeze Off works good primarily on dissimilar such as removing steel bolts from aluminum manifolds. Spray once every 5 minutes for 30 minutes to get the bolts really cold.

Some folks do a mixture of auto transmission fluid and something else for a home brew penetrating oil.

Best penetrating oil is Kroil Oil Grainger usually stocks it.

Gary
....

[Keith M.]

Re: Diff Mount Bolts Stuck

Keith,

CRC Freeze Off works good primarily on dissimilar such as removing steel bolts from aluminum manifolds. Spray once every 5 minutes for 30 minutes to get the bolts really cold.

Some folks do a mixture of auto transmission fluid and something else for a home brew penetrating oil.

Best penetrating oil is Kroil Oil Grainger usually stocks it.

Gary
....

Thanks. think that mixture is with acetone. not gonna do that. Yep I know Kroil well, more from my other hobbies, have plenty...will give that a squirt. PB has never let me down in the past....we shall see.

[Patrick H.]

Re: Diff Mount Bolts Stuck

Once I get it cleaned up and Evaporust should be able to have a better sense. Thank you for calling my attention to this.
Keith

I was thinking you could immerse the whole nose in a bucket of Evaporust to see if that helps remove the corrosion and free it up.
This is as long as you're going to rebuild the differential, of course.

[Gary C.]

Re: Diff Mount Bolts Stuck

Keith,

Spray often for a day or two with Kroil Oil and keep it well soaked. Takes a while to penetrate that much rust.

Gary
....

[Gary R.]

Re: Diff Mount Bolts Stuck

Most times, a mixture of heat and oils with some impact will break them loose. I had one like that come in from FL years ago. The bolts were mushroomed over and not moving. I cut the ends off and removed the bracket, then disassembled the diff completely. I got the rear bolt out but the forward one was in there tight.

I set it up in the Bridgeport and figured I would drill out the bolt, but after about 1/8" it rolled the bit. Set up an endmill to cut it out and that went another 1/4" and rolled the mill. Never had one like that before or since but I sure remember it. I machined a rod to fit the hole, then got the housing cherry and one hard hit broke it loose without any damage to the housing.

[Mark E.]

Re: Diff Mount Bolts Stuck

I just learned a few new techniques.

I was going to recommend several steps: soak in ATF/acetone mixture (typically the most effective penetration lubricant), then use Freeze-Off (I've had a can for years but only needed it once in a hopeless situation... which worked), then apply an impact wrench to shock it loose.

But I like Patrick's idea of immersing it in Evapo-Rust. Try that as a first step to remove the rust.

Since it's out of the car, a good plan B is to use a press.

[Joe L.]

Re: Diff Mount Bolts Stuck

Hi Joe,
Hmmm...prolly looks worse in the photo than in person. I will keep an eye on it but til now I only see surface issues and it would appear to have adequate integrity. Once I get it cleaned up and Evaporust should be able to have a better sense. Thank you for calling my attention to this.
Keith

Keith------


It looks like much more than surface rust to me. It might still be functionally OK but it at least appears to have some erosion of metal at the nut seats.

Also, the same rust conditions that affected the plate is probably the root of the problem you're having with removing the bolts. Has this car lived for at least part of its life in an area with salted rods?

[Keith M.]

Re: Diff Mount Bolts Stuck

Keith------


It looks like much more than surface rust to me. It might still be functionally OK but it at least appears to have some erosion of metal at the nut seats.

Also, the same rust conditions that affected the plate is probably the root of the problem you're having with removing the bolts. Has this car lived for at least part of its life in an area with salted rods?

Well...all I can say is that the reinforcing plate remains very thick. I looked at the photo again and believe it looks worse than it is. The key here is get those bolts out, get the rust treated and go from there. Would be willing to bet that when I get to that point if I measure the thickness it will be darn close to any well survived example. As an engineer I am not worried based on what I can observe at this point. To answer you question this was a MA car from birth through 2000 and since then it has been off the road and garaged. Several knowledgeable folks including some of our very own NCRS have seen this car and commented on the relatively very good condition of the frame. Back in 1998 a local mechanic stated he could not adjust the trailing arms as one of the pivot bolts was frozen. I got it out. PB and patience. Same should prevail..eventually...with these two bolts. Another thing I did today in addition to liberal application of Kroil is gave the mount a few good whacks from various angles. That should help provide some shock to the bolts.