7R Block clean, clean,clean question

[HKZ Bob]

I took all studs out of the block and wonder what sandpaper is appropiate for
cleaning the saeling surfaces to match with the three bond spec.
I 600 paper sufficient. Surface gets very clean but does three bond need rougher surface than 600.

What's your experience.

bob

[smessing]

During my rebuild, I have used only Scotchbrite pads on all my sealing surfaces. For my case halves, I used the pads, along with brake cleaner, and the surfaces came out very clean, and not scratched.

I would probably stay away from any sandpaper, which would leave scratches in the metal, and keep from obtaining a tight seal.

Scott

[tom1394racing]

I've been told by the local experts to only seal the case perimeter surfaces and not the internal surfaces like the bearing saddles.

I know this is different that what is recommended in Wayne's book but I was told that sealant on the bearing saddles might cause those critical surfaces to not mate properly.

[cstreit]

Gasket cleaner and scotchbrite pads are sufficient. I wouldn't use any harsher abrasive...

[BURN-BROS]

You may have to block sand the area where the case studs have the tendency to pull. The 2 long perimeter studs on the front below #8 main. The two #8 studs and the long intermediate shaft stud. All of these really need time-certs to prevent them from pulling in the future.

[rcwaldo]

Originally Posted by BURN-BROS

You may have to block sand the area where the case studs have the tendency to pull.

^^That is very good advice --- sometimes you'll find the area local to a stud to be proud of the flat mating surfaces.

[BURN-BROS]

I use 400 grit on a long flat bar. Once you see minor scratches on the area of the perimeter seam that has not been affected you will be around .0005 from being true. I like to stop right around this point as you will quickly lose your reference point.. Do a quick touch up with 600 grit and your good. I do this before I have time-certed these areas but It can be done after but make sure the time-certs will not stand proud of the reconditioned surface

[HKZ Bob]

thanks burn bros,

do you mean these bolts.




Greetings bob

[Grady Clay]

Guys,

Keep in mind there are two different home-use Scotch-Brite pads; the green Heavy Duty version and the blue All-Purpose version. The Heavy Duty is an abrasive pad and isn’t appropriate for the sealing surfaces. With care, the All-Purpose can be lightly used with lacquer thinner or brake clean.

There are industrial versions of Scotch-Brite pads used in the auto body industry and others. These are inappropriate for case sealing surfaces.

I like finding the correct solvent for whatever type sealant was previously used and use the least abrasive wipe.

Best,
Grady

[BURN-BROS]

Originally Posted by HKZ Bob

thanks burn bros,

do you mean these bolts.




Greetings bob

Bob,

The two on the right that you have circled are not the ones, the other three that you have circled are correct

All the studs are on the left side of the picture.

The # 8 main bearing is the large aluminum cylinder that the front seal mounts into. Those studs that are immediately above and below it are the last two problem studs.

[HKZ Bob]

Are we takling about the studs around the 8 bearing. See picture ?

Greetings Bob

[BURN-BROS]

Yup Yup!