Hydraulic Pump Quad Ring

[310farmer]

I'm rebuilding the hydraulic pump on my 1974 310 John Deere backhoe. The shaft seal went out. I have replaced the worn (had small grooves worn into it) shaft with a new one and have a new RE29103 seals kit. In checking to make sure things fit right, I tried the outer dust seal on the shaft and it fits perfect. The quad ring, however, fits very loose, maybe .o30 or .040 slop. In other words, the inner diameter of the quad ring is larger than the diameter of the shaft. There is also a teflon backup seal/washer and when 'dry' fitting it and the quad ring in the housing where they go, that all seems like a nice fit, but no way is the quad ring going to make a nice seal on the shaft. My question is this: Is this normal? Is the seal 'made' where the quad ring fits up against the teflon backing or where it mates with the shaft? Seems like it should be both. I have double checked all the part numbers and everthing checks out, but I'm wondering if the wrong quad ring is in this kit. The new shaft is identical in every way to the old one.

 

[LarrySTN]

Are you trying the quad ring in the pump body or out of the pump body? The quad ring will be compressed some in the pump body and should make it snug on the shaft. The teflon backup will not tighten the quad on the shaft.

 

[310farmer]

Thanks for your reply. So it sounds like the seal does need to make good contact with the shaft? I"ve tried it both ways. Out of the pump it is sloppy loose, when it"s in the pump body a little harder to tell of course, but with the teflon backup and quad ring in place you can look in from the end and see that the inner diameter of the quad ring is lower than the inner diameter of the teflon backup. I don"t think it can possible touch the shaft surface. I"m not familiar with how quad rings seal and thought maybe the high oil pressure some how forces the seal hard enough into the teflon backup to make the seal, but this some how seems unlikely.

 

[Tx Jim]

310farmer
Here's JD's specs on the quad ring

Part Number: R39729
Description: QUAD DOUBLE-BAK-BON SEAL
Specification
Weight 0.02 LBS 0.01 Kg
Inside Diameter 1.421 IN
Nominal Section 0.139 IN
Standard Number Code A
Standard Number Size 221
Durometer 70
Material TB715

 

[310farmer]

I'm away from the shop this weekend so I won't be able to measure my seal to see what I have for a few days, but I'm guessing the 1.421 is what I have. Again, I'm going from memory here, but I think the shaft OD is 1.375.

 

[Tx Jim]

Spec's for pump shaft for a non-serialized pump. Do you have a non-serialized or serialized pump??????????

Part Number: R34348
Description: SHAFT,HYDRAULIC PUMP
Specification
Weight 3.66 LBS 1.66 Kg
Length 7.362 IN
Pitch Diameter A1 1.167 IN
Teeth - A1 A2 A3 14
Major Diameter 1.964 IN
Minor diameter 1.248 IN
Material EX14H

 

[310farmer]

I'm not sure which pump I have. How do I indentify serialized or non-serialized? I couldn't find any numbers or tags on the housing. The JDparts website says it is an AR101807 pump so that is what I ordered parts for. The R34348 shaft is what I ordered and is identical to the old shaft as far as the measurements go. I think the 1.964 dimension must be the cam lobe at it's largest point, not sure where the 1.248 dimension is, maybe the OD of the splines. The area of the shaft where the bearings are pressed on is 1.375 and where the quad seal rides is the same as the bearings minus a few thousands. The seal that is supposed to be included in the RE29103 kit is the R39729. That seal has a spec of 1.421 ID and the shaft it rides on is 1.375 or a little less. Something doesn't add up. Do they make a different quad seal with the same OD but a smaller ID?

 

[Tx Jim]

The replacement serial numbered pumps has a SN tag the original pump doesn't.
Here's the spec's for SN pump parts

Part Number: R77611
Description: SEALING WASHER
Specification
Weight 0.00 LBS 0.00 Kg
Inside Diameter 1.251 IN
Outside Diameter 1.405 IN
Thickness 0.090 IN
Durometer
Material TEFLON

Part Number: R79152
Description: SHAFT, HYDRAULIC PUMP
weight 3.46 LBS 1.57 Kg
Length 7.461 IN
Pitch Diameter A1 1.167 IN
Teeth - A1 A2 A3 14
Major Diameter 1.744 IN
Minor diameter 1.248 IN
Material ADQL-3

 

[Tx Jim]

Both pumps use the same tapered roller brgs part # JD8192 with inside dimension of 1.375 IN .
The shaft for the SN pump doesn't look anything close to being machined the same as the non-SN shaft. You could view them both on JDparts.com as I did

 

[310farmer]

Thanks again for all you help. It's much appreciated! I have the non-serialized pump. No numbers any where on the pump and no tags. And after reviewing jdparts, the shafts I have (the old one and the new one) are most certainly for the non-SN pump. So it appears I have ordered and recieved all the right parts.