1994 cat 928f rear end leaking?

[heymccall]

$10k? Is that Canadian?
Dealer doing my 544Js or 426C backhoes is always under $6k.

If you can get the axle out, that's the toughest part, just because of rigging and lifting.

20 hours @ $150...$3k
Parts @ $1k (probably closer to $650)
So, there's $4k
Add another $2k if you go after axle and pinion seals.

If you can get an independent, it should be less.

Did you know, Caterpillar dealers can produce a formal quote.

 

[Nige]

Don’t start panicking just yet. If you had a major brake seal leak you would be losing oil out of the hydraulic tank almost as fast as you could top it up. I am assuming that this is not the case as you never mentioned it.

Have you actually checked the rear axle oil level.? If it is high, drain it down to the correct level and run the machine as you normally would for a couple of days. Keep an eye on the hydraulic oil level during that time. Then go back and recheck the axle oil level. If it is high drain it back to level but this time carefully measure how much oil you drain out. Report your findings. Also mention how many hours the machine operated in that time.

Another question. When was the last time the rear axle oil was changed.?

 

[brendin]

10k is Canadian . They said that’s the worst case. I’ve been busy with work but I’m going to start the process of removing the axel in the next couple weeks. Now I have a question. Why is there clean hydraulic fluid coming out of the diff if the brake seals are gone? I would assume if the brakes were shot it would be dirty old with debris in it from the brakes being shot? Thanks for the help guys .

 

[brendin]

Also do any of you know and website to download a service manual? I looked and I could only find one in French.

 

[Nige]

Please go back and read my last post #22 above, and above all - don't panic just yet.
Do what I suggested in that post and report back with all the requested information before you even consider removing the axle.

If it does come to having to remove the axle there is plenty of information that we can come up with to help you.

 

[Nige]

I just reminded myself that I should never assume..... In this case I was assuming that you either have an Operation & Maintenance Manual or if you don't have one that you already know how to check the oil level in the rear axle.
Just in case you don't, here's how to do it.....
In the 1st illustration below you are looking down from above on the LH side of the rear axle. Clean the area on top of the axle housing and remove #18. You will find that it is actually a dipstick with ADD and FULL marks on it.


If the rear axle oil level is too high, carefully drain some oil out of the drain plug #17 (2nd illustration) that is located on the bottom of the rear side of the differential housing in the centre until the oil level is between the ADD and the FULL marks on the dipstick with the plug #18 screwed all the way into the axle housing. If you ever go to change the oil at any time in the future the fill plug is #1 on the same illustration.

 

[brendin]

I check the fluid. It was so full when I pulled the dipstick out oil started pushing out of there. I drained it from the drain plug now it is at the correct level.

 

[Nige]

OK, all good so far. Lowering the oil level will stop it coming out of the relief valve on the top of the axle, at least for the moment.

What did the oil look like that you drained.? Dark and cloudy or clear and bright, or maybe something in between.? Remember that photos are always good. They help those who aren’t there to see the same thing that you are seeing.

Next thing is to do as I suggested and run the machine for a few days then go back and check the oil level in the axle again. Remember to keep a close watch on the hydraulic tank oil level during that time. If you are losing major quantities of oil past the rear axle brake seals the oil level in the sight glass should visibly drop.

I know I asked the question before but don’t recall a reply. Do you have an O&M Manual.?

 

[brendin]

The oil is say was pretty clean like an 8 out of 10 if 10 was brand new oil. The hydraulic tank is low right now. I’m going to top it up and see what happens in the next bit. I don’t use this machine to often I’m just trying to get it ready for winter.

 

[Nige]

Under those circumstances it may pay you to run it for a bit more than you would normally do just to get a handle on whether the amount of oil leakage you have is significant or not.

Top up the implement hydraulic tank before you start testing.

When was the last time the oil in the rear axle was changed.?

O&M Manual.?

 

[brendin]

No idea when the last time the axel oil was changed as I just purchased it a few months back and no I don’t have a o&m manual.

 

[brendin]

Also. What is the best case scenario here? Say this is a very slow leak and it takes hours for it to fill the diff? Is this something I can leave but keep a close eye on the fluid levels? Or will this need to come out and be repaired either way? In the rear end all that is in there for fluid is hydraulic oil? I thought it would be something thicker.

 

[Nige]

I’ll post some detailed info later on how you can download one from the web. The usual price is around US$45.

Regarding the rear axle oil based on your description of it I am going to advise to hold off changing it until we get to the bottom of the brake issue, because if the worst comes to the worst it will have to be drained anyway before removing the axle for the brake repairs.

 

[Nige]

The oil in the axle is an SAE50 TO-4 oil. The oil in the operating side of the brake system is an SAE10 hydraulic oil.

Under normal circumstances these two oils would never come into contact with one another. Apparently what you have is SAE10 oil leaking into the axle housing, which is why it’s filling up. The $64,000 question is “how fast is the leak and does action need to be taken immediately to fix it or can the machine run for a while like it is.?”

 

[brendin]

Yep. If you could send me that link later it would be of great help. I’m going to change all the fluids in this machine because I have no idea when the last time it was done. If you can find which specific oils for each component and the quantity that would be awesome. Thanks for all the help.

 

[Nige]

OK, for an O&M manual, follow these instructions -
Go to - https://catpublications.com/
Click on "Continue as Guest"
Type SEBU6626 in the window at the top of the page and click "Search". You should see the illustration below - $46 for a downloadable pdf document. If you do go this route and buy a download you need to go to the top RH corner of the screen in the black bar and click on "Login". At the bottom of the popup that appears is a "Manage Orders" button. Click that to actually get your download.

The O&M will contain all the fluid recommendations amongst a lot of other info. If you have any questions after reading it then post back here.

 

[Nige]

My fluid recommendations would be: -
Engine - SAE 10W30 or 15W/40 meeting at least API CG-4 or better.
Transmission - SAE30 oil meeting Cat TO-4 specification.
Axles/Differentials - SAE50 oil meeting Cat TO-4 specification.
Hydraulic System - SAE10W hydraulic oil.

 

[Nige]

Also. What is the best case scenario here? Say this is a very slow leak and it takes hours for it to fill the diff? Is this something I can leave but keep a close eye on the fluid levels? Or will this need to come out and be repaired either way?

If we're talking about a really slow leak it could take days or even weeks to fill up and overflow the differential. That's the idea of setting the oil level correct then running the machine for a few days to see how much the oil level goes down in the hydraulic tank and up in the rear axle. We have to know what sort of leak we're dealing with before making a decision. I've run machines for weeks or even months (under controlled conditions - in other word keep an eye on the oil levels) with leaking brake piston seals because circumstances dictated the machine in question couldn't be stopped to pull an axle out.

 

[brendin]

So I will need to do the seals at some point either way. Well I’ll see how fast or slow the leak is but I think that diff is coming out either way. I need it fixed properly I can’t just keep watching the oil every few days.

 

[Nige]

Sorry but I don't see what's so hard about watching oil levels..?
TBH checking the hydraulic oil level is part of the daily pre-start check.