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Topic: Part Number? Crank Pulley that drive hydraulic pump (Read 509 times) previous topic - next topic

Part Number? Crank Pulley that drive hydraulic pump

I need a crank pully that bolts on the crankshaft and drives the hydraulic pump. My tensioner is bouncing around and the problem is the crank pulley is bent and wobbles.

Does anybody have a part number or source other than FT? It's just so hard to get a hold of people there these days.
1998 U270 34'

Re: Part Number? Crank Pulley that drive hydraulic pump

Reply #1 –
Often, there is enough "slop" in the holes in the pulley that you can "center" it.

Use a piece of chalk and CAREFULLY move in toward the pulley with the engine at idle until it just touches the part with the most  run out.  Turn off engine, loosen/remove belt, loosen bolts securing the pulley and move it away from the chalk mark.

Repeat.

Note, that part of the function of the tensioner is to dampen belt movement.  Watch this Gates Corp video:
Failed versus a good belt tensioner.] [url=http://gatesupdates.com/tensioner/tensioner_video.html]Failed versus a good belt tensioner.[/url]

Brett
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Part Number? Crank Pulley that drive hydraulic pump

Reply #2 –
Brett,

Thanks for the guidance. Before ordering I was going to try exactly what you said!

I may set up a dial indicator to try to avoid too many iterations.

I briefly looked at the pulley yesterday. It may actually be bent...bubba with a hammer (or something). I'll fully inspect today.

Also, my tensioner seems to be angled too much. I have two new tensioners and belts on the way. The belt installed is the correct one, but I'm wondering if it's stretched out, or the tensioner is incorrect. (see attached)

1998 U270 34'

Re: Part Number? Crank Pulley that drive hydraulic pump

Reply #3 –
Also check the bracket that the pump is mounted on.  I have seen them with cracks at the weld.  This allows the belt tension to cant the pump and therefore mis-align the belt.

Just pull up on the long run of the belt with your hand (engine OFF).  That will tell you if the bracket has failed.

And, if the tensioner is angled, that needs to be corrected.  But make sure it is not the pump/bracket first.

Brett
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Part Number? Crank Pulley that drive hydraulic pump

Reply #4 –
For clarification, what I meant by "tensioner angled too much" is that it's pushing too far up on the hydraulic pump belt....as if the belt is an inch or two too long.
1998 U270 34'

Re: Part Number? Crank Pulley that drive hydraulic pump

Reply #5 –
Actually, you want the minimum tension that keeps the belt from slipping.  At least a lot of these pumps have bushings, not bearings and if the belt is over-tensioned, it can pull the front bushing out of the pump.

Belt tension can be changed by changing belt length, OR by drilling a new detent hole for the tensioner.  Been there, done that.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Part Number? Crank Pulley that drive hydraulic pump

Reply #6 –
Quote from: krush –
For clarification, what I meant by "tensioner angled too much" is that it's pushing too far up on the hydraulic pump belt....as if the belt is an inch or two too long.
The pump belt tensioner on our coach looked just like that, tensioner w as almost on the pump pulley. Used a smaller belt and looks OK now and belt is not wearing out, so I think we are good.

Roland
1993 U280 4341
2010 Jeep Liberty
The Pied Pipers

Re: Part Number? Crank Pulley that drive hydraulic pump

Reply #7 –
PN on the pulley is 3914460. Appears to be the same as the 5.9L fan pulley.

I have a runout of approx 0.035-0.040" (a lot). Tracking down if it is the pully or the mounting now. There is not much slop to adjust the pully--and my runnout may be caused by bent or wobble. I remounted the pulley 180 degrees and have same result.
1998 U270 34'

Re: Part Number? Crank Pulley that drive hydraulic pump

Reply #8 –
NOTE: Always use the Gates Belts instead of the Dayco, Dayco belts ALWAYS have a shorter life.

Re: Part Number? Crank Pulley that drive hydraulic pump

Reply #9 –
How'd you know!?? LOL, new Gates HD belts are in the mail.

To end this case. My pulley is fine. There is only 0.005 adjustment in the pulley mount. The pulley has a machined fit (in my world we call it a rabbit fit, no clue why) that limits ability to move the pulley around.

Doing some more runout measurments, the problem was the PLATE that the pulley mounts to. I could see the gap between the circular plate and the harmonic damper was not even. I loosened up the 4 bolts and I could move the plate around. I took a feeler guage and centered the plate up, tightened the bolts, checked it...better.

Bolted it all back together, put the belt on, started engine, and almost no bounce on the tensioner!
1998 U270 34'

Re: Part Number? Crank Pulley that drive hydraulic pump

Reply #10 –
Good job.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020
 

Re: Part Number? Crank Pulley that drive hydraulic pump

Reply #11 –
The Gates vs Dayco Belt issue goes way back in my experience. Being in the industrial engine service business many years, every time we get caught and have to use a Dayco due to local availability, we always go back with a Gates, hoping the Dayco will last a few days until we can return, usually the Dayco will last a few days, but not always.  Between breaking the rib type or the V type turning upside down, they are not worthy of a good word from me.