CAT 3.3b DPF removal(No engine removal or cab tilt)

[Tall.Timber]

Hi all, I recently had to remove the DPF from my 277d and was reading horror stories about the process. Some said to remove the motor. Others suggested tilting the cab and going in from the plate with hydraulics. I figured there had to be a way around this. The following is how I was able to remove and re install the DPF in around 6 hours. This should be a similar process for all 3.3 motors in skid steers. A few sources i saw actually showed the 259d diving more room than the 277d. But either should be possible.

Tools used(may be missing some):
-12mm box wrenches
-14mm box wrenches
-16mm box wrench
-small pry bar
-non-marring mallet
-10mm socket
-16mm socket
-needle nose
-LOTS of profanity

I started by freeing up some room and removing the air cleaner and intake hoses.



Next I got to work on the worst bolt. The 14mm mounting bolt that faces the fire wall. I have long arms which helped this alot. But my large hands made things a bit difficult. But there is room to reach all the way behind the DPF to feel a wrench onto this bolt. I positioned my wrench so that i could use a small prybar to leverage against the DPF to loosen this bolt. Once it was loose it was a game of 1/8 turns until the bolt was out. Once that bolt was out I knew i had this in the bag.
With this bolt removed a went in for the other 3 bolts. The rear ward facing is very easy to access and the bolts on the "driver side" can be felt quite easy and came right off with a 14mm socket and ratchet. These are easy to feel for as they are the only bolts you will feel. If you feel the nut side of a hardware then that is a DPF filter bolt and does not need to come off. We only want to remove the bolts holding the DPF canister to the mounts. I also unplugged the temperature sensors and differential pressure sensor and unbolted their mounts. I then took off the turbo to DPF manifold bolts/nuts. The DPF side has studs so it will not be able to remove until you move the DPF. It was then that i realized the 277d does not have as much wiggle room as the 259d that i had seen. I proceeded to remove the intake horn, throttle body and wiring mounts. This was fairly quick as it was just (3) 14mm bolts holding that intake assembly together. This gave alot of room and if i was doing this again i would do that before removing the "driver side" DPF bolts. With the DPF now able to move around quite a bit i went ahead and removed the (3) temperature probes and (2) differential pressure sensor tubes and mounting plate.

 

[Tall.Timber]

With the DPF moving free and most obstructions out of my way, I began trying to remove the DPF. I kept running into pinch points and after 15 minutes i decided that a new approach would be needed. I opted to split the DPF in the machine and remove it in pieces. I started on the inlet side of the DPF as the DPF canister bolts were less corroded and likely easier to break free. I used two wrenches and a pry bar and this went very easy.
As i removed bolts i was able to spin the entire DPF around to easily access all of the bolts. After removing the last bolt the inlet side of the DPF along with the temperature probe spacer and two gaskets came out very easily. The inlet side contains the DOC so be careful not to damage it when removing. I was then able to swing the remaining DPF out on the "driver side" where the intake horn was removed. The DPF was now out successfully. Total time was about 3.5 hours. Could have been closer to 2.5 had I not had to experiment through he removal.
I preformed my cleaning and then began reassembly. This is essentially the same procedure in reverse. I put my DPF side back in and got it close to its resting location. then put the inlet/DOC side with the gaskets and spacer back in. This side has an indexing pin so you cannot have anything clocked wrong. However the temp probe spacer can be flipped so make sure the hole for the temp probe is facing the rear of the machine, i then began placing my bolts one by one and tightening the DPF back together. Once this was done i put my differential pressure sensor pipes back in but left out the temp probes.
I was then able to get the DPF resting back into place and got the turbo to DPF pipe placed. I then started with getting the mounting bolts lined up with the DPF canister. If found that it was easiest to get the two rearward bolts lightly started and then reach around the DPF to get the awful fire wall facing bolt lined up. This went better than i expected and only took about 5 minutes to line up and get started. Once this was started i did the 1/8 turn shuffle to tighten this back up and then got the "driver side" front bolt started and tightened everything back up. Once that was complete i just put all the minor things back in, Throttle body, temp probes, connectors, exhaust outlet. From this point the removal and install was complete. The reinstallation took about 2.5 hours and that is about as fast as you could do it realistically i think.

After finishing this repair i would not be worried at all about having to do this process again. There are not many places that things can get messed up. Most likely issue would be breaking off a bolt in the turbo. Hopefully my explanation helps someone. I did not want to remove the motor or mess with the hydraulic system to do this repair and i think finding a way to do this with out either is a major win. Anyone can do this in a day in their own shop. Although you will have some very beat up hands, and a much larger vocabulary. I have some additional photos from the process that may be helpful but didnt really fit into the write up. Let me know if anyone is going to try this process.

TLDR; CAT 3.3b DPF is known for being difficult to remove/replace. I was able to do it in 6 hours instead of 12-14 as CAT quotes, and did not have to remove the engine or lift the cab. Anyone with some basic tools and a long evening can do this also.

 

[Nige]

Where there's a will, there's a way.....
Well done and an excellent write-up.