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Cat 931B brake adjustment

Discussion in 'Track Loaders' started by Boss Hog, Jun 30, 2020.

  1. Boss Hog

    Boss Hog Member

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    I bought a 931B a little over a week ago. It had been sitting in a barn for a while. I changed oils and filters, and did other maintenance to get it ready to go.

    When I tried it out, the right brake is strong. The left one works, but only when the pedal is almost on the floor.

    The clutch on both sides seems to disengage with the pedals maybe 2 1/2" down.


    So I did a search on Cat 931B brakes. I found a lot of diagrams that look like the one in this link:

    https://www.heavyequipmentforums.com/attachments/jim-photo-032-jpg.125758/

    But the pedals on my machine are top mounted, up under the dash.

    I read somewhere that the 931 is close to a D3. So I searched on D3 brake adjustments and found this image that looks more like the brake setup on my machine:

    https://ww2-secure.justanswer.com/uploads/DIRTWRENCH/2010-03-27_231205_1.JPG

    I found the housing (#2 in the picture above) in front of and under the battery tray. But there is no vertical adjustment going up to #3 on that picture.

    So I'm stumped. Have no idea where to look for an adjustment. And I'm out in the middle of nowhere, with no Cat dealer around.

    I took pictures of the ID tags on the side of the thing hoping that might give some info that y'all would need:

    Dozer Cat 931 ID tag 1.JPG
    Dozer Cat 931 ID tag 2.JPG

    Thanks for any help you can offer.
     
  2. Nige

    Nige Senior Member

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    Attached the procedure to adjust both the steering clutches and the brakes. You may eventually need both.
     

    Attached Files:

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  3. Boss Hog

    Boss Hog Member

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    Thanks for the quick response. Looks like you've been around a day or two. :)

    Looking at the diagram on page 3, I don't see where adjustment screw #4 is. I attached a pic of my machine looking in from the back, under the battery tray.

    Under battery tray.JPG

    Do I need to remove the seat and AC condenser to get to it?

    To access brake band support screw #7, do you have to drop the belly pan below that part of the dozer?
     
  4. Nige

    Nige Senior Member

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    You need someone with practical experience of working on them to go into that level of detail. I just pulled the procedure out of the service manual.

    Welder Dave ought to know. IIRC he has a 931B.
     
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  5. kshansen

    kshansen Senior Member

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    Well I can't speak to what does or doesn't need to come off to make the adjustments but would put dropping the belly pans and cleaning things out near the top of the "To Do" list! Looking at the picture you posted makes me think the belly pans might be rather full.

    Just be very careful when dropping them do not get in a place where you can get trapped. I would strongly suggest taking one bolt out at a time clean it and anti-seize and reinstall it then move to the next one. Once you know all are going to come out easy then go about dropping the belly pan(s). Be aware that even if the belly pan might only weigh 100 lbs there could be many time that much weight in dirt and debris on them. There could be enough to not even let them come down with all the bolts out!
     
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  6. Welder Dave

    Welder Dave Senior Member

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    There's another recent thread with someone looking at adjusting D3C brakes which are very similar. First thing to do would be clean everything up so you can see what's going on. Then check the rollers on the steering clutch valves under the seat. They are known to get flat spots on them and not fully engage. Look to see if you have the brake band support bolts on the bottom of the steering clutch compartments. They are a square head with a jam nut to hold them at adjustment. If you have these you have dry brakes which are the most common. There's a simpler way to adjust the brakes than measuring all the linkages like is in the Cat manual. Best to remove the seat. Pull the hair pins and remove the pins from the brake rods going to the back of the machine under the seat (shown in your pic.) Then remove the diamond shaped covers on the clutch/brake compartments. The brake adjusters are under these covers. Some newer machines have extended brake adjusters that come outside the compartments but I doubt you have those. Snug the brakes up tight to the brake drums. Don't reef on them, just snug. Then shorten the brake rods you took off as short as possible you can still get the pins back in. Then loosen the brake bands off until you get the proper pedal travel. This guarantee's the free play is at the brakes and not in the linkage. I learned this from the late Bob/Ont who was a Master Cat mechanic and knew these machines like the back of his hand.

    https://www.heavyequipmentforums.co...mpartment-drain-plug.83568/page-2#post-898494
     
    Last edited: Jun 30, 2020
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  7. Boss Hog

    Boss Hog Member

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    Not really looking for suggestions about cleaning rollers or belly pans. Just wanna know were to adjust the brakes at.
     
  8. Welder Dave

    Welder Dave Senior Member

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    The rollers on the steering clutch valves are just as important as the brakes if you want to turn! If the steering clutches aren't fully engaging you're not going to turn. Like trying to turn with the differential lock engaged on a tractor. Between the adjustment procedure Nige posted and the info I posted for adjusting the brake rods you should have enough to see if it's an adjustment problem or something more serious. Not every issue is an easy fix and sometimes a bunch of other work is required to get at the problem in hand. The first thing to do in most cases is clean everything off. I had my steering clutches rebuilt with new brake bands. The brake bands were relatively cheap. The steering clutches not so much, about $3500 per side done at a shop with a press and the proper tooling. This is when I took them in. Little bit of fun getting them out and reinstalled. You don't have to drop the belly pan to see the brake band support bolts. There's a ring protector around them the same as the drain plugs for the finals. The brake adjuster rods are under the diamond shaped covers close to the hump looking things under the seat. You need a socket and an extension. I think they're 9/16" but not positive. They could be corroded so have some penetrating oil handy. When I had mine apart I coated the threads with anti-seize.
     
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  9. Boss Hog

    Boss Hog Member

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    The clutches seem to be working fine. At the moment I'm not worried about them.

    I can not see any sort of diamond shaped cover near the "hump thing".

    Removing the seat was mentioned. But under the seat there's a grate and then an AC condenser. Does that need torn out too?

    I don't have a clue of the brakes are dry or wet, and have no idea how to tell.

    I did notice the rings in the belly pan. but they're full of mud and I wasn't sure what their purpose was. Didn't want to pull one off and find out it was the drain for the fuel tank or something like that.

    I'm a believer in anti-sieze based on many years of working on older combines.
     
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  10. Welder Dave

    Welder Dave Senior Member

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    Do some cleaning so can you see what's what. AC condenser I have no idea about. Clean the mud around the rings on the case bottom and look for the square bolt heads. Nothing has to be removed at this point. The rings protect the bolts and drain plugs from damage. They will confirm you have dry brakes. You need to worry about the clutches because they have to be fully operational for the brakes to work properly. The diamond shaped covers are in front of the "humps" under the seat. Below is a thread from another site. Pay attention to the 2nd post and especially the 3rd post from Bob/Ont. If you're really lost on your new machine, you may have to have someone with experience look at it. There's only so much anyone can do on a forum.

    https://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=crawlers&th=30674

    I found a pic. that shows the covers to get at the brake adjusters. #20 is the covers and #21 are the adjusters in the diagram below.

    https://avspare.com/caterpillar/sebp1247/sebp1247026/#SEBP12470265
     
    Last edited: Jul 1, 2020
  11. Boss Hog

    Boss Hog Member

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    Tonight after work I'll see if the seat and AC coil will come out, and if that gives me more access.

    Thanks for the help so far.
     
  12. Nige

    Nige Senior Member

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    A bit of clarification about "the rollers". Just to be clear no-one was talking about track rollers............

    In the steering clutch & brake control linkage are two small rollers that are well-known for seizing up. If that happens they get flat spots on them and adjustment of the linkages is impossible until everything has been disassembled, cleaned, & lubricated (and probably the rollers replaced as well). As the tractor is an unknwon quantity to you, it may pay to remove everything above the linkages (seat, etc) and go through all the them now, lubricating and cleaning as necessary, just to make sure that whatever problems you have are not a result of worn, damaged, or seized linkage parts.

    Here's the thread about the D3C Dave was referring to, and the linkages on your machine I'm certain will be identical to that model. It started out talking about drain plugs and the linkage adjustment part came later. I tihnk it's pretty self-explanatory. https://www.heavyequipmentforums.com/threads/remove-1989-d3c-clutch-compartment-drain-plug.83568/
     
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  13. Welder Dave

    Welder Dave Senior Member

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    I had linked the other thread in post 6 but should point out if the rollers on the steering clutch valves need to be replaced you have to take them to a dealer to have done. Here is another long thread concerning the steering and braking on a D3B. This machine has wet clutches but has a lot of info about the steering clutch valves.

    https://www.heavyequipmentforums.com/threads/d3b-clutch-and-cylinder-rebuild.79487/
     
  14. Boss Hog

    Boss Hog Member

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    Well, I pulled the seat off tonight. Only to discover that the plate under the seat is welded to the sides. So there's no access from above.

    Only think I can think to do now is pull the battery tray out and see if that helps any.

    Nige, I do understand no one was talking about the track rollers. At this point I have not figured out what rollers you're talking about or where they are. For now I'm gonna stick with trying to figure the brake out. Once that's done I'll figure out what to do from there.
     
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  15. Welder Dave

    Welder Dave Senior Member

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    Have you looked at all the links posted? For the umpteenth time, the steering clutches have to be fully engaged for the brakes to work properly and they're fairly easy to check. If you're not going to read the links or pay attention to what people are telling you they will stop responding. Show some pics of the seat and everything around and under it.
     
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  16. Boss Hog

    Boss Hog Member

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    For the umpteenth time, all I asked for help with is finding out how and where to adjust the brakes. The clutches seem to be working fine, so at the moment I'm not concerned about them.

    I have not had time to read through all the links. I work full time and come home to take care of the farm. The time available to deal with this is very limited. That's why I'm focusing on one thing at a time.
     
  17. Welder Dave

    Welder Dave Senior Member

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    No sense fixing your machine because you'll never have time to use it. If you don't have time to read the links explaining how the brakes and steering clutches work together you're never going to get your machine working properly. The steering clutches have to fully release before the brakes will do anything. The tracks are basically a solid axle. In order to turn you first need to disengage one side with the steering clutch. Then the brake can be used to slow or stop that side allowing the machine to turn. If the steering clutch isn't fully releasing, there's still power trying to turn that side. You can have brand new brakes adjusted perfect but if the steering clutches aren't fully releasing all you'll do is wear your new brakes out while going in a straight line. Do yourself a favor and do some reading so you understand how the brakes work. They aren't like brakes on an AG tractor.
     
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  18. Boss Hog

    Boss Hog Member

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    The fact that I asked for some information does not obligate me to do what you suggest.

    When I did some searching for a solution to this problem I found some old threads on this forum. I figure I'll keep posting what I find in case someone else is looking for information.


    Here's a look at the front of the seat assembly before I pulled the seat:

    Seat 1.JPG


    Here's a look at the left side of the seat area with the seat removed. I also removed a plastic air duct, which explains why you see the unpainted area.

    Seat 2.JPG


    Here's a closeup of the front edge. As I said earlier, it's obviously welded. So no access through the seat area.

    Seat 3.JPG
     
  19. Tinkerer

    Tinkerer Senior Member

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    Ummm, What part do you not understand that the clutch and brake adjustment are interrelated ?
    Two members that know all there is to know about your problem explained the procedure a couple of times and you ignore them.
     
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  20. Welder Dave

    Welder Dave Senior Member

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    Not that I'm obligated but I would hazard a guess that a previous owner welded the seat support in. My machine doesn't have a cab but if I recall there are angle iron brackets bolted to the fuel and hyd. tanks that the seat base bolts to. I can't see Cat welding the hyd. and fuel tanks together to support the seat when everything else is bolted. Channel iron supports under the seat look like they could be homemade too. Cats aren't always the easiest to work on but having to remove the hyd. and fuel tanks as a unit to do service doesn't make sense. Probably best to check with Cat. Curious what the whole machine looks like.