23 replies to this topic

[hanra]

I had thought I had been using the correct methods when it came to sealing surfaces...

I re-fitted my diff centre and used a paper type gasket and #3 sealant, Ive noticed its started to weep again where the carrier meets the housing....

Ive also just noticed a little puddle of oil under the gearbox.... which I just recently put back in after replacing the incorrect input shaft cover...

I cleaned all mating surfaces, fitted new paper type gaskets, applied #3 sealant to both sides of the gasket and torqued all bolts up to GMH specs.

I suspect the gearbox is leaking from the front input shaft cover again, around the drain channel that is designed to drain oil from the input shaft cover back into the gearbox...

This is where it was leaking from previously, and it appeared that the oil had just soaked through the gasket and a sort of capillary action effect took over...?


Should I be binning the gaskets and sealant altogether and use a modern type of silicon sealant with NO gasket??????

I cant believe I have to pull the gearbox and diff centre out again, after using what I believed at the time to be the right method.....

This is the sealant Ive been using with gaskets...






Previous leak which I thought I would have fixed 2nd time around....However I didnt use any sealant at all the first time around. 2nd time around I used a new gasket and #3 sealant.

Edited by hanra, 01 April 2013 - 08:32 PM.

[hanra]

Maybe I should try this stuff.

 

http://www.permatex....et-maker-detail

[S pack]

Brad

 

I had the same problem with my banjo diff leaking. Pulled it back out and installed two gaskets. Problem solved. I did use permatex gasket cement on all surfaces but can't remember whether it was the non hardening or hardening type, most likely the #4 hardening cement as it's the only bottle I've had in the cupboard for years.

 

Did you put thread sealant on the gearbox front cover bolts? Try the #4 cement on the cover gasket.

[hanra]

I used #2 sealant on the bolt threads for the input shaft cover. And #3 on the mating surfaces of the cover itself.

I can't quite tell just yet where the gearbox leak is coming from..... It could be the rear extension housing? It has a paper gasket with #3.... The puddle was the size of a 50cent coin under the gearbox, and the entire bottom side of the box is oily. The car had been sitting for a few weeks for this to happen.

Either way.... It's box and diff centre out again. I'm thinking that permatex stuff I linked to used without a gasket will be the go.

[S pack]

I would use a gasket on the front gearbox cover to maintain the correct tolerances.

[dattoman]

I use #3 also

And don't get leaks where I use it

But realistically its doubtful your diff flange is flat on the housing after all these years

Hence that leak

 

If in doubt I get a surface linished on a bif flat belt sander .... or use different and extra sealants

[sibhs]

Hi Brad,

I presume the gearbox pics was without sealant?

Cause I would expect to see the gasket goo on both surfaces. You mention applying goo to gasket, I would apply to metal surface as well.

 

I'm a home mechanic with no training, take my advice at your own risk.  Might give a pro an idea on what is going on here.

 

Good luck

 

Marty

[hanra]

I would use a gasket on the front gearbox cover to maintain the correct tolerances.

The permatex stuff can be used with a gasket also apparently according to the website.

[hanra]

Weve always used that sealant in our workshop but on stubborn items the toyoya silicon type sealant seems to be the best i think its called toyota black seal packing on their system

 

 

Are you refering the permatex gear oil RTV? Hopefully I can source it locally.

 

 

 

 

Any yes that pic of the gearbox input shaft cover was my first attempt... just a gasket, no sealant at all. I had no idea what to expect honestly.... and I didnt remove a gasket from it originally.

 

 

 

Dave Im worried that the oil is penetrating into the gasket and weeping through the paper, if that makes sense. Ill do the diff first, as I know where that leak is, Ill leave the gearbox for a week or so now that the car is up in the air, Ill have a better chance at spotting where its leaking from.

[UCgazman]

This stuff - http://www.ebay.com....=item23292b902e the yanks love it...

Edited by UCgazman, 02 April 2013 - 05:23 PM.

[TerrA LX]

Plus 1 for mating surfaces not flat.

[tuxedoss]

On paper gaskets I always used the GMH head stud sealer, not sure if its still available but never had a problem with it. It's like a solvent glue, has a very strong smell. Won't work like a silicon on uneven surfaces though. Over the years I used this on the diff and gearbox and front timing case and never had a leak.

[Uncle Chop Chop]

The GMH head stud sealer is still available through GMH spares.

 

To the original question, if it doesn't seal with Permatex, the mating surfaces are not flat enough.

[hanra]

Plus 1 for mating surfaces not flat.

I've had two different input shaft covers fitted and its still leaking.... So I guess the cast gearbox casing itself is not flat? Pretty hefty that stuff. How does it bend?

[TerrA LX]

^ same way the bumper bar did spose.

[hanra]

Come again?

[TerrA LX]

Have another beer Brad.

[Struggler]

I haven't used a gasket to seal a diff centre for years. RTV Silicon FTW.

 

I also wouldn't hesitate to use it on your gearbox snout or extension housing.

 

Don't go crazy with the stuff, just enough to seal it up.

[Rob2408]

I'd have to agree with Struggler and Blownv6hatch. I used to have the same problem you are experiencing, dropped the gaskets used only silicone and torque to spec, problem solved. I used to use CRC Electraclean to clean matching surfaces though.

Cheers

[Uncle Chop Chop]

Metho will get it clean and dry. Or Brakleen.