Cat 955L pinion bearings, steering clutches and undercarriage oh my!

[workshoprat92]

on the topic of 955L steering clutches my 955L I have the LH pinion shaft and carrier out of it. entire steering clutch assembly had to come out to get to it. Also LH final drive disassembled. I need to get my LH final drive back together. If i check end play on the RH pinion shaft and flange it is pretty large or so I think. Does anyone know what this end play should be? I cant find anywhere in the manual where it would say whats acceptable. Its large enough the very outside friction disk has bent fingers on the splines where the drum has bent them over when being released and no longer lined up with drum splines. I think the only way this can be done is with this large end play. I need to figure out why this is causing this issue. Has anyone seen anything like this?

Reply by tctractors

The top pinion should have a small amount of end float (in-out) from the pinion roller bearings, the B/Drum flange should also have only a very small amount of lift-tilt to it with good bearings on the pinion, the in -out float is usually around an 1/8" but more or less than this figure is not an issue, on the flange tilt on the outer edge it could be 3/16" as a max or around that spot but there is lift and float, its not much trouble to pop off the flange and pull out the pinion re-sealing the shaft as you go, as for the disc issue a picture would be handy to see.
tctractors

 

[workshoprat92]

That's not a bad idea. I already have the steering clutches out of the tractor and disassembled. It would be far easier to pull the pinion from inside the steering clutch case than to pull final drive down to have a look. I will get some pictures and get a good measurement on the in out float. It sticks in my mind its close to a good 1/4" Probably why the LH outside pinion bearing failed and then proceded to trash the outside final drive case. I already have a new case cover. I bought the machine with this impediment.

Ok I think I need to explain the history of this machine. I bought this thing for 7K. When I bought it it had the LH final drive dissembled and LH track frame off it. The reason the fella was selling it was that he says he was doing pond work. the LH pinnion outside bearing went bad and it cut a hole on the LH final drive case. by the time they noticed it the final was full of pond sludge. He had a half assed mechanic pull the thing apart and see what it needed. I think thet realized what a project it is and gave up on it. He was had it advertised as parting out and fortunately I was able to get there first and buy whole thing before anything was sold off it. We looked at it very closely and even drug batteries out to it and started the engine. We felt real comfortable it had enough salvage value with a good running engine and a real good undercarriage which I needed for another machine. Plus it had good tight pins and bushings on bucket and arms and I figured I could swap that assembly on my other machine and not need a bunch of repair work there. We had to slap the final, track frame and track back on it good enough to roll onto a trailer. Fortunatly he had another machine we used to push it on our trailer. I got the thing home and used a bunch of parts off it to get my other cat up and producing revenue again. Mainly undercarriage parts. SO my partner and I have now decided to put this other machine back together. we have a real good idea of what we need parts wise and what the cost is gona be. we already have some of the stuff we need due to making some deals and collecting undercarriage parts. I have everything I need to put final back together and need the parts for the steering clutches. We figure all total we can get this machine back in revenue producing condition for about 5-6k. We think this is in our best intrest because when we are done we cannot buy a workable machine for this kind of money. As the machine sets now it is up on blocks (real red neck stuff) with no track frames on it. also LH final drive is disassembled and the steering clutch assembly is out of it. I have spent hours cleaning mud out of steering clutch case that puked in past inner pinnion seals into the clutch case. fortunately oil kept everything from rusting. I pulled the bottom plug on the case and used a cut down barrel and parts washer pump to help with cleaning. It worked great but I do need to do a final rinse and wash.

Anyhow here is some pictures of when we went to pick it up

 

[workshoprat92]

In this picture you can see the hole in the case that caused all the issues. I can tell someone else had worked on these finals before by the tell tale silicone use. I don't think whoever worked these final did a real good job and im not real sure they got the right bearings on the pinion shafts causing to much end play. I think this end play is what caused the bearing failure. I need to research that more but may need to pull RH final apart to get bearing part numbers.

 

[Nige]

I need to research that more but may need to pull RH final apart to get bearing part numbers.

No need for major surgery like that. Post the machine Serial Number and someone will get the Part Numbers for you.

 

[workshoprat92]

No need for major surgery like that. Post the machine Serial Number and someone will get the Part Numbers for you.

I am sorry if I was not real clear on that thought. I meant pull the final drive apart to see what bearing is actually installed on the machine. It runs in my mind the parts guy at cat once told me there is three different bearings one could get for that pinion bearing. I need to ask him about that again. I am wondering if someone before me installed the wrong bearing causing the large amount of end play. something just isnt set up right somewhere and its causing issues with the brake drum mashing the innermost friction disk spline fingers over and even breaking some of them off. I will try to get a picture of one of these bad discs this morning. I really think this is the root cause for the pinion bearing to fail and trash out the case like it did.

 

[tctractors]

Firstly the top pinion bearings are pin located in the outer case also the inner housing, it is possible to weld repair the outer case wear /damage and have it re-bored to standard spec' CAT have a jig for this repair that bolts to the case, the top pinion needs a small amount of end float if possible so the roller bearings are not under load on their roller ends, as for the bearing part numbers I would check also your pinion part number? the complete clutch in a photo would be good, also its best to join the track over the back sprocket for ease of working not with all that carry on you have in your snap, I like the Red Neck rim pull set, getting things to bits is easy sometimes? but its tricky to press things back together without the correct tooling, If you were in the U.K. I would soon press things back for you.
good luck tctractors

 

[workshoprat92]

Firstly the top pinion bearings are pin located in the outer case also the inner housing, it is possible to weld repair the outer case wear /damage and have it re-bored to standard spec' CAT have a jig for this repair that bolts to the case, the top pinion needs a small amount of end float if possible so the roller bearings are not under load on their roller ends, as for the bearing part numbers I would check also your pinion part number? the complete clutch in a photo would be good, also its best to join the track over the back sprocket for ease of working not with all that carry on you have in your snap, I like the Red Neck rim pull set, getting things to bits is easy sometimes? but its tricky to press things back together without the correct tooling, If you were in the U.K. I would soon press things back for you.
good luck tctractors

TC thanks so much for the replies! I do know about the bearings being pin located. still if they are the wrong size it can cause to much end play. I need to look at it better and see if the pin location is somewhere short of the race bottoming in the bore. If so the doofus that worked on this before I did might have not known about the pin and drove them all the way to the bottom causing to much end play. Just a possibility I guess.

On the weld repair of the case I very well thought of that as its cast steel and not cast iron so it will weld and is repairable. However I found a good used replacement case delivered to my door for $500 and have already purchased it. I did not think that to bad a price and dont think I could get it repaired much less than that. even if i could it wouldn't be but maybe a couple of hundred dollars difference and its worth it to me to have an unmolested case. I don't think the doofuses that shipped me that case and pulled the bearing races out knew about the pins. the plugs are still in the pin bores and still has a pin in it. I dont know how the hell they got the races out unless the pins sheared. I have new pins and plugs already. Here is a pic of the new case on a pile of the steering clutch cover and such.



I do understand about the top pinion needing some float as the straight roller bearings just aren't meant for side loading. But how much is to much? It takes some end play to be able to get the pinion flange away from the drum to get steering clutch assembly out. again if its so much the inner most friction disc is floating outside of the drum and the fingers getting bent over then its to much. But where is the problem and thats the mystery. the bearings I bought and the pinion shaft I bought match the parts numbers called for in the parts book. I can disassemble the RH side and see what some other doofus installed but the LH side parts were all destroyed in this catastrophe and are well beyond any clues. I still have it all and can look at it better when I get a chance.

Here is a couple pics of the inner most LH and RH discs that would disengage the drum with the excessive end play. notice the bent and missing spline teeth. as far as an assembled picture im far beyond that point as you can see by the pic of my steering cluch assembly on the pallet setting under my aircraft frame.









On the track we kinda had to deal with it where it layed in the field and was short on options. I also preffer to button it up at the sprocket.

The puller was borrowed from an old man that has been working on these back to the 70's. when we pressed the drive sprocket on our other machine we borrowed his other puller to install the sprocket. I had pulled the sprocket on our other machine to replace a duo cone seal that was cut to shreds from a wad of wire.

 

[workshoprat92]

Here is a pic of the disc as it should be. I don't know why I couldn't post this on last post unless there is a limit to how many pics you can post in one posting. Also is a pic of the machine as it sets now.

 

[workshoprat92]

Here is why I say some hack worked on this final drive. Notice the silicone indicating a hack was in it already. Also look at the pic of the bearing pin plug. notice the bore is plugged with silicone. When I took a pick and pulled the silicone out there was no pin installed to retain bearing. It looked like some jerkwad used a half inch drill bit to remove a 1/4" pin making the pin bore useless. Just more clues to the puzzle. I am thinking If I get this LH final back together with all new parts and it has much less end play then I really need to pull down the RH one and figure out what some hack messed up!

 

[workshoprat92]

Well it was a rainy crappy day and didn't have much to do today. I had to hit cat dealer to get some bolts for a tooth shank for our other machine. I spent a good hour and a half talking to the parts guy who told me there were three different bearings that you could get for the pinion shaft on the outside case side. This is where a good experienced parts man is a very valuable asset. New parts guys just wouldn't know about this. There is in fact 3 different bearings and 3 different races you can get for this pinion. Reason is it has been changed and superseded 3 times since machine was built. The first change came only 1 year after this machine was built. When we called caterpillar support line we found that each bearing had a different width. the first bearing used was 25MM and the second one was 31MM with the third bearing measuring 35MM. each bearing needs the correct race that corresponds with the bearing. the bearing and race are not sold as a set. bearing and race are sold separately so it is very possible to get a parts man that dosent know any better and get a 31MM bearing with a 35MM race! This would definitely cause a problem of way to much end play. I don't know why cat dosent sell the bearing and race as a matched set eliminating the confusion and possibility for this screw up.

From here I really need to pull apart my RH side final drive and see which bearings are installed. It must come apart anyhow as the pinion has to much end play. whatever is installed I need to install the correct race to its matching bearing width.

 

[nicky 68a]

I agree on pulling both sides apart.Good luck

 

[Nige]

Well it was a rainy crappy day and didn't have much to do today. I had to hit cat dealer to get some bolts for a tooth shank for our other machine. I spent a good hour and a half talking to the parts guy who told me there were three different bearings that you could get for the pinion shaft on the outside case side. This is where a good experienced parts man is a very valuable asset. New parts guys just wouldn't know about this. There is in fact 3 different bearings and 3 different races you can get for this pinion. Reason is it has been changed and superseded 3 times since machine was built. The first change came only 1 year after this machine was built. When we called caterpillar support line we found that each bearing had a different width. the first bearing used was 25MM and the second one was 31MM with the third bearing measuring 35MM. each bearing needs the correct race that corresponds with the bearing. the bearing and race are not sold as a set. bearing and race are sold separately so it is very possible to get a parts man that dosent know any better and get a 31MM bearing with a 35MM race! This would definitely cause a problem of way to much end play. I don't know why cat dosent sell the bearing and race as a matched set eliminating the confusion and possibility for this screw up.

From here I really need to pull apart my RH side final drive and see which bearings are installed. It must come apart anyhow as the pinion has to much end play. whatever is installed I need to install the correct race to its matching bearing width.

I agree with you about selling the race and bearing as a set, it would make things much easier. However it may be that in other applications any one of the 3 races (or bearings for that matter) might be paired with something different, hence selling as a matched pair might not be feasible.

Regarding the 3 different bearings/races, is it something to do with the case or with the pinion, or both..? Does the selection of the correct bearing have to do with machine Serial Number as you appear to indicate above and what happens in the case of a machine that's had a case put on it from a machine from a different Serial Number range..? I agree with you that it has to be right so if you want to post a Serial Number I can get details of what mates with what and email them to you if you like.

 

[tctractors]

I would think the pinion would also change if the bearings are changed spec' the bearings need to be fitted all the way home in the housings with the race fitted all the way home on the pinions, if I recall the pinion shaft seals through 2 shaft seals on the inner case as the back of the brake drum flange is some distance from the seal area, I would not think CAT would change the outer case main detail? to remove the bearings from the outer case don't be tempted to use a cutting torch as you will distort the case, I hack out the rollers then weld a strip of scrap to the roller path using this strip as an earth post, then run a bead or 2 of weld around the path, then let cool and lift free, the dowel thing is easy to sort by drilling the plug out 1/2" then screwing a little bolt in to the dowel and tug it, the flange to pinion press up I think is 15 to 20 ton the rim press target is 35 to 40 I think but can check? always go to the low targets first then check the distance spec' even on any torque tension settings always go for the low setting first and see how lock plates fit up, as it gives you scope to tighten more to fit the lock plates on the dead shaft etc.
tctractors

 

[workshoprat92]

I don't know guys i'm just going by what the parts man told me. I just need to get my RH final apart and look and measure. Nige is there anyway you can find out what the end play should be for the pinion shaft and flange when installed? Have any of you guys ever seen this much end play causing the issue with the clutch discs?

The way this is all set up the end play to the outside of the tractor away from the steering clutches is going to be controlled by the outside pinion bearing and race. That just has to be where the deficiency lies.

 

[Nige]

I must say your logic regarding the end play is spot on from my perspective. If someone has rebuilt the finals with narrower bearings/races than what should be in there then the pinion end play will be excessive and by implication it will throw all the weight into the steering clutch assembly.

Drop me a PM with the machine Serial Number and your email address. I'll see what I can dig up regarding Part Numbers and specficiations.

 

[tctractors]

The best way I can describe the amount of end float you should have on your top pinion is "Just Noticeable" the usual top pinion seals are Duo Cone Seals that are on the common tractors like D6 D8 etc, these tend to hide pinion end float by their structure, your pinion seals with heavy duty Lip Seals that allow movement, when I build up a F/Drive I always check the the pinion " Fit " that is is it turning freely, then I check for lift and end float, D8's have lift and end float bit it is minimal, D6 tractors struggle to have end float or lift but need to turn freely with No seals (Duo-Cone) fitted, when this easy turning is found I then install the seals, so on your 955 F/Drive that I have done on possibly the total range 12A H/K/L I cannot recall any with end float worth a comment, it is minimal.
tctractors

 

[AllDodge]

This may or may not help, Have my L manual but has K for final drive. The K manual states: Using 5F989 Plug, 5F9885 (threaded against the shoulder on the sprocket shaft), and a 5F9892 Pin, drive the sprocket shaft into the bevel gear case (with the key slot facing upward) until the distance between the face of the outer bearing cage holder (hand held in place on the taper or the sprocket shaft) and the parting line between the final drive case and the bevel gear case is 10.34 +/- .062

Install the sprocket shaft retainer nut and tighten securely. To lock in place drill a 5/16 hole through one of the notches in the nut through the nut and into the shaft to a depth of 1.14 in.

Other words then : The distance between the face of the sprocket hub and the shoulder spline should be .12 +/- .06

Preload final drive bearings by turning the adjusting nut counter clockwise, apply torque of 1050+/- 150 ft lb

Has pics

 

[tctractors]

AllDodge, your detail is book correct but in practice the shaft must be located tight as these shafts spin in the case, all that measurement stuff is for after the dead shaft is clubbed home, the K and L series loaders are pre loaded in different style. tctractors

 

[workshoprat92]

Tc that is pretty much what I thought on the end float. I will try to get a vid of the end float that I have on my tractor this weekend. I can put a dial indicator on it if need be and take pics.

 

[Nige]

A dial indicator reading of the end float would be a good idea IMO.