resealing differential covers

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[ARCHIVED THREAD] - resealing differential covers

Posted: 6/23/2017 2:42:34 PM EDT

Got a couple questions about resealing differential covers.

1. is the black RTV gasket maker the right stuff to use in? Some guys say to only use this stuff, some say the felt gaskets are the way to go, and some say to use a combination of both.

2. If using only the gasket maker how long do you need to let it set up before you reinstall the diff cover and fill with fluid?

3. How tight do you go with the cover bolts, to a certain torque spec or just tighten them up really good with a hand wrench?

These are kind of stupid questions but I want to start doing more stuff myself instead of paying a mechanic to do simple stuff like this.

Posted: 6/23/2017 3:05:22 PM EDT

[#1]

First let me start by encouraging you to get a Chilton repair manual for your car. For $30 you can find your answer to just about any questions you may have on this matter and others in the future.

I personally use whatever came off the vehicle, if it had RTV, then RTV goes back on it. If it had a gasket, I put on a new gasket. Some people (myself included) use a tiny amount of RTV to "stick" the gasket onto the cover - or differential - prior to putting the cover back on (mainly to hold it in place). I torque the cover bolts to whatever the manual says (or find this information online). After the cover is on and torqued, I fill it up. I don't wait for the RTV to dry. The RTV you put on will dry in time.
Now if you use nothing but RTV, you may have to wait about 30 minutes prior to filling up the diff so the sealant has time to "skin".
Good luck!

Posted: 6/23/2017 3:11:56 PM EDT

[#2]

My uncle is a master mechanic and he did mine while I helped. Most import thing is to remove debris from old RTV/gasket, so the metal is smooth and shiny. A drill or dremel with a brush makes quick work of buffing that crap off. Then we applied the RTV, and I don't remember how long we waited for it to set, but not long, twenty minutes maybe? I expected him to use a torque wrench, but he just made sure it was good and tight.

Posted: 6/23/2017 3:19:18 PM EDT

[#3]

What was on it originally is the proper answer

Posted: 6/23/2017 3:38:38 PM EDT

[#4]

I have never had an issue using Permatex Ultra Grey only on Mopar 8 3/4 rear ends. Apply it, set the 3rd member in and pull it tight. Let it skin (about 30 minutes) and torque to spec.

Posted: 6/23/2017 3:52:26 PM EDT

[#5]

Degrease with acetone. I use Permatex Ultra Black. No gasket unless it is a third member going into a housing. Then a gasket is required for proper alignment.

Posted: 6/23/2017 6:30:59 PM EDT

[#6]

When I was rebuilding submersible pumps for a living the blue loctite gasket maker (587) never had any more dry time than it took for me to complete the assembly before I filled the unit with transformer oil for testing.

Posted: 6/23/2017 6:58:53 PM EDT

[#7]

No shop regularly waits for the gasket maker to set up.

Clean the old off, apply the new, tighten the bolts down, fill with fluid, job complete.

Posted: 6/23/2017 7:36:04 PM EDT

[#8]

Thanks guys. I'm in the process of working on the cover now. Ford only put RTV on the this so that's what's going back on, I got some Permatex Ultra black RTV. I got everything cleaned up really good and right now have the cover back on with the bolts hand tight. I'm going to eat quick and go back out in 20-30 min and tighten the bolts the rest of the way.

Posted: 6/23/2017 8:12:40 PM EDT

[#9]

Quote History

Quoted:
Thanks guys. I'm in the process of working on the cover now. Ford only put RTV on the this so that's what's going back on, I got some Permatex Ultra black RTV. I got everything cleaned up really good and right now have the cover back on with the bolts hand tight. I'm going to eat quick and go back out in 20-30 min and tighten the bolts the rest of the way.

View Quote

That's how I do it.

Posted: 6/23/2017 9:26:29 PM EDT

[#10]

The best product ive found is GM engine sealant. WOrks great on diff covers. Ive had horrible luck with RTV, I could never get it set right and always leaked.

Posted: 6/23/2017 9:43:29 PM EDT

[#11]

Yamabond 4

Then torque those bolts up good.
"Strip them up tight, then back them off 1/2 turn".

Posted: 6/24/2017 7:22:42 AM EDT

[#12]

Quote History

Quoted:
Yamabond 4

Then torque those bolts up good.
"Strip them up tight, then back them off 1/2 turn".

View Quote

I think the guy who assembled the front diff must have used a 1" drive impact because those bolts were a bitch to get out with the small 3/8" drive socket wrench I was using

.
The rear cover wasn't so bad except for the one bolt that the assembler partially rounded the head on

. It had just enough bite left for me to be able to get it off and reuse it, next time it comes off it'll have to be replaced. I ended up putting that bolt on top just in case it isn't quite as tight as the others, although I got it snugged up pretty good.

I checked the bolts before taking them off and they were tight enough that I couldn't snug them up anymore with the wrench I was using so I put them back on as tight as I could get them. I went through a tube and a half of RTV so they should be sealed up good

.

Posted: 6/24/2017 8:05:12 AM EDT

[#13]

I have done it every proper and piss poor way imaginable with little to no issue.

red, black, blue gasket maker, regular gaskets, etc. .... Just bolting it on, waiting for gasket maker to setup, etc.

Just get it clean, put something on there and bolt it on.

Posted: 6/24/2017 12:23:00 PM EDT

[#14]

Quote History

Quoted:
The best product ive found is GM engine sealant. WOrks great on diff covers. Ive had horrible luck with RTV, I could never get it set right and always leaked.

View Quote

On a diff??? I have never seen a diff leak when using RTV of any kind.

Posted: 6/24/2017 12:49:22 PM EDT

[#15]

Quote History

Quoted:

On a diff??? I have never seen a diff leak when using RTV of any kind.

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Apparently, im talented like that.

I have horrible luck with using that type of stuff, ended up using one of those RTV-less gaskets, worked pretty good. On the front I used GM engine gasket stuff

Posted: 6/24/2017 8:33:20 PM EDT

[#16]

i use whatever tube of motorcraft rtv is in my caulk gun at the time, and then bill out what the book calls for, for warranty purposes.

its a diff. they aren't real picky. if i'm resealing a front cover or an oil pan ill use what the book actually calls for.

Posted: 6/25/2017 10:08:48 AM EDT

[#17]

I use lube lube locker gaskets on my jeep now. They are reusable allegedly

Before that I would just use permatex ultra black

Posted: 6/25/2017 10:29:42 AM EDT

[#18]

Quote History

Quoted:
I think the guy who assembled the front diff must have used a 1" drive impact because those bolts were a bitch to get out with the small 3/8" drive socket wrench I was using

.
The rear cover wasn't so bad except for the one bolt that the assembler partially rounded the head on

. It had just enough bite left for me to be able to get it off and reuse it, next time it comes off it'll have to be replaced. I ended up putting that bolt on top just in case it isn't quite as tight as the others, although I got it snugged up pretty good.

I checked the bolts before taking them off and they were tight enough that I couldn't snug them up anymore with the wrench I was using so I put them back on as tight as I could get them. I went through a tube and a half of RTV so they should be sealed up good

.

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:
Yamabond 4

Then torque those bolts up good.
"Strip them up tight, then back them off 1/2 turn".

I think the guy who assembled the front diff must have used a 1" drive impact because those bolts were a bitch to get out with the small 3/8" drive socket wrench I was using

.
The rear cover wasn't so bad except for the one bolt that the assembler partially rounded the head on

. It had just enough bite left for me to be able to get it off and reuse it, next time it comes off it'll have to be replaced. I ended up putting that bolt on top just in case it isn't quite as tight as the others, although I got it snugged up pretty good.

I checked the bolts before taking them off and they were tight enough that I couldn't snug them up anymore with the wrench I was using so I put them back on as tight as I could get them. I went through a tube and a half of RTV so they should be sealed up good

.

holy smokes, there's no reason to torque-to-spec anything, much less use an impact.

it's a cover, but if you decide to torque it's probably specified around 25 foot-pounds