I discovered a fraying 6 rib belt on my Detroit 6V92TA hydraulic pump, but noticed both drive and pump pulleys were 8 rib. Turning to the trusty Foreforum resources, I found the following thread (among others):
Belt tensioner on 6V92TA (https://www.foreforums.com/index.php?topic=30208.msg260191#msg260191)
My take away is two fold:
1. the angular alignment of the tensioner is very important and may require shimming.
2. The planar alignment of both pulleys (and tensioner) are very important.
Most posts I have found reference the angular alignment, but few talk about the planar alignment (with exception of saying it is important).
I have measured and think I need to bring the hydraulic pump pulley toward the back of the coach about 1/4" to get planar alignment. The bolts in the big mounting bracket do not appear slotted, so I need to remove the whole assembly to slot the mounting holes and facilitate sliding it out a bit. A potential easier fix would be sliding the pulley out on the pump shaft 1/4", but that seems to risk putting too much stress on the pump bearing.
I haven't figured out how to remove the pulley from the pump yet.
Any guidance or experience share on hydraulic pulley removal or mounting bracket mods to align the pulleys?
Thanks all!
Appears my photo of the pulley shows two approximately 1/4 bolt holes. I will clean them out to see if they are threaded. Maybe they are jack screws used to push the pulley out?
They are for pushing the pulley off the collar and then you can readjust the collar on the shaft for where you want the pulley.
I didn't read the first part. You use the jack screws to push the pulley off the collar and the tap a screw driver in the slot in the
collar and then the collar can be taken off or moved to adjust were you want the pulley.
Good photos, especially the mount to block bolts. Yes, you can slot the mount and move it. I almost did that but my 8 rib is still completely on the roller. I ran a straight edge across from crank pulley to pump pulley but looks as if you basically have done the same thing. How was the angle on the tensioner roller compared to the others and the big mount? Did you see my small washer I fitted between the mount and the tensioner? You may not have the discrepancy. Don't think 1/4" movement will on the pulley will put any more strain on the pump bearing. The other option would work with a round file on the four mount to block holes to elongate them.
If you take the mount off, you might think about putting in the correct block heater under the compressor mount. It's a different heater than the thermostat housing heater. That one is straight, the bottom block heater is curved.
Again, a little more care in the engine and accessory installation was needed. I'm sure this cost several owners a new engine when the belt failed, the DDEC shut down the engine and the operator because of not knowing better or being in a dangerous location, used the override repeatedly and damaged the engine. Such a shame.
Pierce
After fighting with it for two days, I gave up on removing the taper bushing from the sheave and removed the whole bracket with the pump still attached.
A friend helped machine out the slots in the mounting bracket this morning. We slotted 1/2" additional, though I estimate only 1/4" was needed. The setup on the knee mill was problematic based on the depth of cut needed (1.375") and the support gussets on the bracket. We had to do some impromptu cutting out of the gusset plate to offer clearance to the mill quill. It's not pretty, but it is functional!
With the modified bracket mounted, aligned and tightened, the 8 rib belt tracks perfectly!
The old Dayco tensioner was bouncing around a lot, so I sourced a new Gates from Napa. The Gates sticks out slightly further than the Dayco (~1/16"), and aligned better with the belt anyway. It runs smoothly now - no jitter!
Thanks to all the great folks here, I now have much more confidence in the setup!
It looks perfect! Good job. So much hair pulling when the slots could have been in there from the start. Seems like the jig for the original mount was off a quarter inch. By spending another minute machining the mount, Detroit owners would not have to figure it out themselves with a few engines lost because of it.
Like the overhead shot showing the belt right in the middle of the roller.
Pierce
Thanks Pierce!
Feels good to have everything lined up!
Like the fact that the young man is getting "hands on" experience as well.
Also like the hearing and eye protection.
My two oldest kids have been a huge help with getting this coach ready for full timing. Got them involved with the wet bay and bulkhead repairs too - my son especially loved the welding!
It's great to be able to grant some early hands on experience with all the systems on this coach. We even did an impromptu 20 minute homeschool lesson on different types of pumps, and used the coach hydraulic pump as a hands on experiment to see how turning the pulley moves the fluid. All the kids enjoyed that one!
In my experience and opinion your homeschooling is the most wonderful gift you can give your children. And in the end it is a pretty amazing gift you give yourself as well.
Richard