My hydraulic pump is leaking into the crankcase now that I've re-sealed the tank and return lines properly. I see in the CAT parts book that there are two lip seals that can be replaced, but there are no other parts shown for the pump, except for a "rebuild kit" PN: 9J765. I don't see how you could remove the old seals without splitting the pump apart. The pump body clearly needs to be resealed, but there are no gaskets / seals shown in the parts book. So, what am I missing. Does the rebuild kit have the required additional parts? Local dealer doesn't seem to have a clue besides "just buy the kit and find out".
The 9J765 kit says it contains seals and retainer. That should include the shaft seal and possibly an "O" ring for the pump case joint.
If you order the seal kit don't forget the 5F-3106 seal for mounting the pump(that number does change to a 175-7904). Also unless you have a good assortment of orings one of 4J0522 seals and one of the 4J0524 seals and if not replaced recently 11.5 cm of 5P1292 hose for the suction line.
Thanks for the replies. Looks like it's a Parker 20 series hydraulic pump. Already have the front lip seals and body to accessory case o-ring. I'm assuming that the hose end fittings to pump body are both standard code 61 sizes and I have tons of orings for them. Never reuse orings when I break things apart. Suction lines are brand new. Actually had to use OEM parts for that, as they appear to have enough flex to seal right. Generic hydraulic return hose of the same size would not seal against the pipes, even with T-bolt clamps, not to mention starting to disintegrate in the sun in under month... I'm not inclined to buy the kit just to discover what is in it. For stuff like o-rings and seals, I've taken to measuring and ordering parts of my own specification. That way I can decide to use high resiliency Viton on an o-ring ring rather than paying 5x for a generic buna-N part from the dealer. Not too fond of fixing stuff multiple times and been burned by quality issues with OEM heavy equipment parts way too many times.
Tomorrow I’ll take a look in a resource that I have and post the breakdown of the 9J765 Kit.
Thanks, that would be greatly appreciated. Have the pump apart and it looks like there is an o-ring for the body and another cut o-ring type seal against the rotor plate as per the picture. The lip seals were hard as rocks and of course wear groves in the shaft that I'll need to sleeve. The drive gear was actually loose even with the bolt tightened down. Looks to be about 0.002 too short for the given shaft size. Wonder if someone forgot to install a bottom washer or used an incorrect top washer that is suppose to be domed. Be interesting to see if there are parts missing.
I can pretty much confirm what OM posted above. The info is hard to track down but it seems as though the kit only contains the joint o-ring and the shaft seals. The problem is that there are no separate P/N's for the internal parts of the pump which makes tracking down info a bit of a challenge. Out of interest did you ask for a price on the kit..? There is a procedure for installing wear sleeves, Cat reference SMHS6915 "Installation Of Wear Sleeves For Repair Of Groove Wear Caused By Lip-Type Seals" I'm not sure if some or all the info in it might be of help to you. Regarding the gear slop, is it possible that someone used an incorrect lock or washer under the bolt head..?
The biggest problem I see with trying to used the repair sleeves on this pump is the shaft were the seals ride is the same diameter as the section where the bearing/bushing rides. The only possible way to way to install one of those sleeves would be to install on shaft after pump was assembled and before the seals were installed in housing. Not saying it would be impossible but.... Is there by any chance a Cat part number stamped in the pump housing? Something like a 3G4661 ? Parts were at one time available for these gear type pumps but it took a lot of digging to find the parts break-down information on them. Most parts books would only show the seal kits but with a good parts person and some work I was often able to find parts right down to the bushings pressed into the housings along with all those other parts like the brass plates and plastic bits behind them!
The price of the kit was just a few dollars more than the two lip seals, think it was right around $40. That's why I didn't think it contained any of the internal parts. I have o-ring cord coming to re-make the interior high to low seal and a guess at the closest dash number oring for the two halves of the case. The distance between the lip seals requires that two sleeves are needed to fix the groves in the shaft. I have not been able to find a copy of SMHS6915, but I expect it covers using multiple sleeves and filling in the grove with epoxy before installing the sleeve due to the pressure the seal will exert on the shaft during operation. I'll post the part numbers I used for the internal parts and some pictures once I know everything is working right. The leals seals from CAT are made by SKF and obviously Viton. Had a CTP branded seal with the same PN sitting around and it's made of soft buna-N. That would have not lasted very long given the pressure and temperature the pump runs at.
Good point about the sleeved area having to pass through the bushing in the front housing. If sleeved from the front after assembly, the housing becomes captive. Looks like there is only about 0.001 clearance between the shaft and bushing, not enough to pass a sleeve. Might make more sense to try and shim the seals to a different location as there is 0.106" from the top of the outer seal to the end of the housing.
Well if that is an 8J6330 pump it appears many of the other parts are available. I did check and some say contact dealer but most do show a location. Just an example gear 9T1269 shows as being $153. and gear 9T1259 shows as $230 then the seal kit # 9J4729 is $73.
just curious, what does npr mean?
I could be wrong but believe it's: Numerical Parts Record That is Cat Speak for "Look Here For More Information!" If you are viewing that page in SIS and you click one the "NPR" it will take you to a page that may give you anything from the new part number that replaces the one shown, a link to a article on a "Special Instruction" that lists that part. If you have higher level of access than I do you can also see service bulletins about that part.
gotcha, thanks
Interesting... Do the isolation plates show as being available? 4T9425 and 4T9426. The pump has 4 parts in that location. An aluminum plate on one side, two plastic parts and a rubber seal on the other. Question is, does the "isolation plate" include all 4 parts or just the aluminum plate? The isolation plate and pressure plate show a gap between them on the diagram that is not present on the pump, perhaps an error or attempt at making the illustration clearer?
It gets to be a little confusing here when checking on the isolation plates it says contact dealer. As for the rubber or plastic parts in that area I'm thinking they would be in the 9J4729 seal kit. But I can not find anything that gives an actual break down on that kit number. If someone else reading this has access to Service Magazines it appears there are three that relate to the 9J4729 kit: SMNV0689 SMFE1290 SMJL2897 Not sure about the way the parts book makes it look like there are three things stacked up there but my guess is they are showing the pressure plates as two parts, they are seal backings with a bronze layer on them against the gears. Another thing is the pressure plates is a bit more confusing where the pump shows two of 9T1276 when I run that number it comes up with two different numbers. 364-6564 and 364-6565. Sorry I can't be of any more help
The D&A procedure for the pump certainly makes mention of multiple plates during the process. To the OP, you said above that you thought the pump on your machine was a Parker Series 20. I'm thinking that the 8J6330 pump is more likely a Tyrone pump, but I may be wrong. Attached a couple of docs that may be useful.
It probably is a Tyrone pump, but Parker bought them as far as I can tell, so whatever the Tyrone PN was, it's probably been changed, or the pump replaced by something Parker makes. I'll have the parts to try and re-assemble it tomorrow and let you guys know how it goes. The isolation plate seals are still somewhat pliable, so I will reuse them if the oring stock rubber doesn't work out. I think I will try moving the inner seal lower to move it's contact points out of the old groove and move the outer seal further out to do the same. Or I may install the two sleeves after the pump is together and then press in the seals over the shaft. Thanks again for the help.
I'd be adding up the individual parts cost if it gets out of hand. That's a common pump used on the 3306, 977, D5, D5B. I see complete after market pumps as low as $700.
Yeah Permco would be at that price or maybe less
I find it rare that I can rebuild a pump cheaper than I can replace it. By the time you add up the parts cost, your labor time, and the downtime, it usually is more money than you would think.
Finished the pump re-assembly tonight. Hopefully some of this info will hel someone else down the line. Everything below is verified information, as in I used the parts listed / measured it myself. Pump: 3G4661, part of the 8J6330 Hydraulic pump assembly. Listed as "Type 2" in my old parts book for 153 hydraulic system for a D5B. Pump part number is stamped on the rear of the case between the inlet / outlet ports. Inlet is a code 61 -24 size 1.5" and outlet is a code 61 -20 size 1.25". O-ring seal for the two case halves is a Dash 156 size, 3/32 thick. Viton replacement from McMaster is PN: 1288N253 Oring for the pump to engine accessory case is a Dash 250 size, 1/8 thick. Viton replacement from McMaster is PN: 1288N268 The two lip seals for the inlet shaft are 2.0" OD, 1.25" shaft dia and 0.43" thick. Made of Viton with hard sealant on outer sides. Current seals from CAT are made by SKF. Rotor plate seals can be made from Viton oring cord stock of 1/8" (0.139" actual) thickness. As the original seals are pre-shaped, using the cord stock can be challenge since it wants to spring out of place or deform the plastic carrier and push it into the way of the rotor bushings during case assembly. The rotor bushings appear to be teflon coated. The pump stack up consists of a 4 piece seal set, an end plate made of steel with bronze facing the rotors, the rotors themselves, a top end plate and another 4 piece seal set. The seal sets consist of an aluminum spacer, a thin clear plastic holder for a rubber seal, a formed rubber seal and a hard plastic backing plate. The thin clear holder has a U cross section to hold the oring like rubber seal. The pump uses two stacked lip seals to keep the hydraulic fluid out of the engine. The back of the first seal is vented to the pump inlet to limit the pressure seen by the seal. There is a spacer between the seals and a groove cut into the case so that any oil making it past the first seal should be vented to a drain hole at the bottom of the front of the housing and outside of the engine. This drain hole has a very small valve in it, with a spring loaded check ball to try and keep dirt out. The valve's two exit ports are located at the sides of the valve, which looks like a bolt with a hex head. It's pressed into the body, though it would appear to be screwed in at first glance. The drain holes get plugged almost immediately making this vent almost useless. Even though my seals were leaking several gallons a day into the crankcase, not a drop came out of the vent. There is enough space in the hole where the lip seals are pressed to seat new seals about 1/8"+ higher than normal, avoiding any wear groves that may exist on the input shaft. It is possible to re-sleeve the shaft with two sleeves, but it needs to be done after the housing is re-assembled as the sleeves won't with through the shaft bushing in the housing. Using the sleeves would of course require removal of them if the pump needs to be disassembled at some point. The input shaft has 22 splines with a 0.942 OD and 3/4" spline length. My gear was loose on the shaft due to the spline being about 0.002" longer than the gear is thick. No obvious reason for this was visible. I put the heavy washer that holds the gear onto the shaft on a lathe and faced 0.010" out of center area where the shaft hit the washer to move the clamping force back to the outer edge of the gear. The rotor end plates looked to be in good shape as did the rotors and housing so they were all re-used. There was an obvious casting void in the middle of rotor area in the aluminum housing. Seems the factory thought this was OK and used it anyway. No crack propagation or other defect expansion was visible. All exterior hardware was replaced. Total cost for the rebuild was just over $100. Additional pictures in next message.
More pictures... Regarding the cost of rebuilding vs. replacement, my view has changed over time as I've been burned so often with aftermarket and OEM parts. The starter died on this machine and I first replaced it with a cheap aftermarket. That failed, stuck in the ON position, after the first start. Thinking I learned my lesson, I replaced it with a CAT rebuilt. That had parts falling off it within the first hour of run time. Luckily I had the guards still off and I noticed the missing solenoid cap. Seems that having enough threads for the cap to be installed with 1/4 turn was good enough for the rebuilder. As the machine is in a very remote location, reliability is my number one priority, thus rebuilding things myself is actually a time saver since I know they are done right. Wish I didn't have to, but...