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Topic: Hydraulic Pump Belt Alignment - 6V92TA (Read 520 times) previous topic - next topic

Hydraulic Pump Belt Alignment - 6V92TA

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

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!
1994 Grand Villa U300 40' Build: 4396
6V92TA Detroit 350HP
Allison 4 Speed w/jake

Re: Hydraulic Pump Belt Alignment - 6V92TA

Reply #1 –
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?
1994 Grand Villa U300 40' Build: 4396
6V92TA Detroit 350HP
Allison 4 Speed w/jake

Re: Hydraulic Pump Belt Alignment - 6V92TA

Reply #2 –
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.
Peter and Frieda Morin
1999 36ft. U320 Foretravel
Build # 5436
1998 Suzuki Sidekick Sport

Re: Hydraulic Pump Belt Alignment - 6V92TA

Reply #3 –
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.
Peter and Frieda Morin
1999 36ft. U320 Foretravel
Build # 5436
1998 Suzuki Sidekick Sport

Re: Hydraulic Pump Belt Alignment - 6V92TA

Reply #4 –
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


Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Hydraulic Pump Belt Alignment - 6V92TA

Reply #5 –
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!
1994 Grand Villa U300 40' Build: 4396
6V92TA Detroit 350HP
Allison 4 Speed w/jake

Re: Hydraulic Pump Belt Alignment - 6V92TA

Reply #6 –
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
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Hydraulic Pump Belt Alignment - 6V92TA

Reply #7 –
Thanks Pierce!

Feels good to have everything lined up!
1994 Grand Villa U300 40' Build: 4396
6V92TA Detroit 350HP
Allison 4 Speed w/jake

Re: Hydraulic Pump Belt Alignment - 6V92TA

Reply #8 –
Like the fact that the young man is getting "hands on" experience as well.
Future Foretravel Owners
2019 Jeep Cherokee Trailhawk
Retired USAF, Retired DOD Civ's
FAA A&P, Indust. Eng., Acft Depot Lvl. Maint.
Larry and Becky Rountree

Re: Hydraulic Pump Belt Alignment - 6V92TA

Reply #9 –
Quote from: master2301 –
Like the fact that the young man is getting "hands on" experience as well.
Also like the hearing and eye protection. 
Jan & Richard Witt
1999 U-320  36ft WTFE
Build Number: 5478 Motorcade: 16599
2011 Jeep Wrangler Unlimited w/Air Force One
Jan: NO5U, Richard:KA5RIW
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Re: Hydraulic Pump Belt Alignment - 6V92TA

Reply #10 –
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!
1994 Grand Villa U300 40' Build: 4396
6V92TA Detroit 350HP
Allison 4 Speed w/jake
 

Re: Hydraulic Pump Belt Alignment - 6V92TA

Reply #11 –
Quote from: Chip7 –
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
Jan & Richard Witt
1999 U-320  36ft WTFE
Build Number: 5478 Motorcade: 16599
2011 Jeep Wrangler Unlimited w/Air Force One
Jan: NO5U, Richard:KA5RIW
The selected media item is not currently available.