Construction and other equipment - HD7GB loader rear engine seal #

Print Page | Close Window

HD7GB loader rear engine seal #

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Construction and other equipment
Forum Description: everything else with orange (or yellow) paint
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=206797
Printed Date: 07 Jul 2025 at 10:20pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: HD7GB loader rear engine seal #

Posted By: Braswell
Subject: HD7GB loader rear engine seal #
Date Posted: 20 May 2025 at 8:48am

I have the wet bellhousing and I need seals for the crankshaft . There are 2 separate seals … one facing the engine and the other facing the bellhousing. They are identical National # 77286HC I’ve tried a few places to match them up but I need the Original Allis Chalmers part number for them. All I can find is the seal for a dry bellhousing housing.
Reliance sent a seal they say is a double lip but it sure doesn’t look like one . Any help appreciated or where to find the parts manual
Randy

Replies:

Posted By: Codger
Date Posted: 20 May 2025 at 10:40am

What is the serial number of the tractor and engine? Four, or six cylinder?

-------------
That's All Folks!

Posted By: Lazyts
Date Posted: 20 May 2025 at 12:45pm

74029500 seal from Minnpar is about $50. Pretty sure the 670 had same rear seal as 685/11000 series.

Posted By: AC Mel
Date Posted: 20 May 2025 at 3:04pm

Yes...I concur with Trevor....that part number should be 74029500...available from Minparr. should be applicable to tractor serial numbers 27201-27950 and 34U27951-up. My parts books do not show any configuration of 2 seals....have no idea of what you might have going on there? Yes that seal is the same for both the 3500 and 11000 engines

Posted By: DMiller
Date Posted: 20 May 2025 at 3:55pm

Problem with a Gb is they use a IVECO Engine. Totally Different Animal.

Posted By: AC Mel
Date Posted: 21 May 2025 at 12:03pm

Dave...The original 7GBs had the 3500....we have 2 of them. I think any GB with an IVECO...probably was put in for a replacement. The dealers were pushing that conversion big time after Fiat took over. We have a 645 with that conversion from the 3500 AC. Actually a pretty good running engine...but have trouble finding parts

Posted By: DMiller
Date Posted: 21 May 2025 at 6:17pm

All the Gb's that I perused around here had Iveco on them. Back when was having real concerns with the old 7G

Posted By: Codger
Date Posted: 21 May 2025 at 6:29pm

The ones I seen of course that were new were IVECO powered. Older ones I seen had the 3500 engine, or the 344, (I think) four cylinder Allis engine.

-------------
That's All Folks!

Posted By: Braswell
Date Posted: 17 Jun 2025 at 5:22pm

Codger, thanks for responding… this is the 6 cylinder turbo 3500 engine with a wet converter housing.
The machine serial # is 34U29793
The picture in the service manual shows back to back seals on the crankshaft.
Thanks for the help!!!

Posted By: Codger
Date Posted: 17 Jun 2025 at 7:07pm

I don't have a manual for that exact model but I've checked by another loader, and farm tractor using the 3500 engine and neither show a back to back seal. All show two "O" ring seals, and a lip seal. The lip seal retains crankcase oil in the engine of course, and the two "O" rings seal the flywheel housing to the rear of the cylinder block.

Looks to be a very common setup. Lip seal part number is: 74027280. Larger "O" ring is: 74025097, and smaller "O" ring is: 74020879. You could always pop the seal from the bore and direct measure also. Easy to match it up when the sizes are known.

Hope that is some type of help.

-------------
That's All Folks!

Posted By: Braswell
Date Posted: 17 Jun 2025 at 9:09pm

Thanks for the effort!!!!
This machine has a wet converter housing so the extra seal is to keep the transmission fluid from running into the engine. I have the national seal number and measurements but no one can come up with a match.
Thanks again
Randy

Posted By: Codger
Date Posted: 17 Jun 2025 at 11:06pm

Both applications I cited are powershift with wet torque converter housings. I've never seen more than a single seal in a lot of machines I've been into over the years myself. An uneducated guess is someone installed a second seal as there is a groove cut into the sealing surface of the crankshaft hub. They make "speedi sleeve" to repair this and the seals used with these are special for those sleeves/rings. It would be very difficult to source just the seal without the wear ring as they are a matched set. Many times the sleeves are called "Wedding Bands" also.

-------------
That's All Folks!

Posted By: Braswell
Date Posted: 21 Jun 2025 at 3:49pm

Hey… thanks again. My book show two seals . I tried to take you a picture but no matter how small I make it, it says it’s too large to load

Posted By: Codger
Date Posted: 21 Jun 2025 at 6:15pm

Alright, I wish I had access to your manual because that is an oddity for me. I have a National Seals catalog from the late 50's to early 60's and I'll see if I can round that up. I've tried several oil seal conversion websites but had no success. You don't have the machine apart do you? If so the bore, and crankshaft hub could be measured up for fitment.

Much easier to get a replacement seal from measurements than replacing an old part number at times for something obsolete; BTDT.

-------------
That's All Folks!

Posted By: Braswell
Date Posted: 29 Jun 2025 at 10:21am

Good morning Gentlemen… I’m still struggling for rear crankshaft seal(s) this is a 3500 turbo with a torque converter bolted to the bell housing. My service book shows two identical seals on the crank. One facing the engine, the other facing the converter housing… I have this setup in my 7gb but I can’t find the AC part number for them. I’ve tried Applied Industrial out of Atlanta but they can’t cross the National number nor match by size. The seal Reliance is sending is not a double lip seal. 474029500k they say it is but it’s not really a double lip seal… that’s why AC used 2 seals back to back. I have a picture of this but it won’t load here. The national number is 77286HC
You help is appreciated!!!!
Randy from NC

Posted By: Codger
Date Posted: 29 Jun 2025 at 12:55pm

PM me your email address. I'd like to have a copy of your manual.

Thx,

-------------
That's All Folks!

Posted By: Braswell
Date Posted: 30 Jun 2025 at 6:17am

Drbraswell@triad.rr.com
Sorry, I don’t know how to PM you

Posted By: Codger
Date Posted: 30 Jun 2025 at 11:26am

Sent you a pm.

-------------
That's All Folks!