1954 HD9B Engine Clutch rebuild
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=156802
Printed Date: 29 Jul 2025 at 7:18pm
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Topic: 1954 HD9B Engine Clutch rebuild
Posted By: cariboo4x4
Subject: 1954 HD9B Engine Clutch rebuild
Date Posted: 30 Dec 2018 at 11:11am
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So clutch pressure plate has lots of heat spots. I don't recall seeing cracks in pressure plate yet will look again. . Flywheel is covered in heat spots and radial cracks. Service Manual says we can remove Sixteenth inch of material. I spoke to an ace machinist and he says he can resurface flywheel and possibly pressure plate. Clutch drive plate looks fine yet I'll measure it for thickness spec today. Neighbor says clutch would slip in 2nd gear. I'll post more photos later today or tomorrow, When I have removed clutch pressure plates on regular trucks, I back off each bolt a 1/2 turn in a repeating star pattern so tension slowly releases. I did this and pressure plate did not come off. See photo. It wasn't until we pried pressure plate off with two opposing pry bars that pressure plate popped off. I been reading service manual and still trying to figure out how pressure plate assembly functions to put pressure on clutch disc. Heading out to shop today to see how it exerts pressure. I wonder what the availabiluity is on new, used, or refurbished parts?  nap"? |
Replies:
Posted By: cariboo4x4
Date Posted: 30 Dec 2018 at 3:38pm
 So one photo of flywheel wear and tear. I flipped pressure plate over and seen these cracks. As the pressure plate sits on work bench its is disengaged. I'm thinking as it is engaged these cracks are causing pressure plate to not fully grip clutch disc. Going to take it apart and see how it works. |
Posted By: cariboo4x4
Date Posted: 30 Dec 2018 at 8:10pm
| Looks like a Back Plate is needed, part number CL-8303. I wonder if anyone here has that part in good used condition? |
Posted By: MACK
Date Posted: 30 Dec 2018 at 8:16pm
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Don't it have a ring to adjust for more pressure on clutch? As far as heat cracks, don't worry about them. MACK |
Posted By: Rick
Date Posted: 31 Dec 2018 at 2:20am
| Mack's right...I can see the adjustment tab in the second picture. I would resurface the flywheel, but not worry about the cracks as were mentioned...it'll be fine. How is the clutch disc? Thickness? Rick |
Posted By: cariboo4x4
Date Posted: 31 Dec 2018 at 10:20am
| Clutch thickness is 7/16" using my measuring tape. It still has lots of material. Flywheel side worn a tad thinner than pressure plate side. Miss-placed my calipers. Back Plate which mounts on pressure plate is cracked so will try to find another back plate. Not sure if we can weld back plate. I'm thinking back plate is under tension when clutch adjuster ring is adjusted. |
Posted By: cariboo4x4
Date Posted: 21 Jan 2019 at 10:34am
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I located a good used part in Australia of all places. They describe themselves as the biggest dismantler in the southern hemisphere. So good used back plate is coming in as airmail. Philhuntparts.com.au |