drive belt not slipping

[38racing]

I working on an old husqvarna freebie. LR121 95414001 . 1996. When the clutch/brake is applied the belt keeps moving and turns the transaxle pulley so that you can't shift gears. Shifts fine if engine is off. If in gear the forward motion will not stop completely with the clutch/brake applied. (haven't adjusted brake yet and didn't test with engine off , in neutral, brake applied for rolling resistance). The clutch engagement pulley seems to be moving to its maximum disengaged position. Its belt guide has only one fixed position. All other belt guides appear to be in place. The belt is loose. I removed the belt. IPL calls for 126520 which appears from my AM supplier to be 1/2 x 88 1/4. Belt on it is marked 12-8516 (rotary 1/2 x 88 3/8) and it appears to cross to an AYP 144200. My AM supplier shows 144200 as 1/2 x 88 5/8. Measuring the belt on it with a cloth tape gave me about 88 1/2. So if spec belt is 88 1/4 it should not be belt size causing the problem. Possible that rotary belt wider than spec belt or are most AYP 1/2 all same width?. On the engine pulley the drive V is quite deep so belt does stay in groove when loose. Pulley appears to be OEM. I did drop it. There was some rust on the groove surfaces. I have removed that with a dremel. Any thoughts about whether that might solve my problem and what else to pursue if it does not?

[KE4AVB]

It could one those that uses the 1/2 x 88-3/4 belts as one version does use a different engine pulley. And I seen ipls to be wrong sometimes. Though I have one Cub Cadet here that all the aftermarket suppliers were trying to sell 1/2" when the mower had 7/16 belt and belt retainer would not allow the belt to develop the needed air cushion.

[38racing]

I just measured belt again. Once on basement floor and once along the basement stairs handrail (to ensure a straight roll) . Both came out at 88 inches even. So maybe belt is 1/4 too short. I guess that I will reinstall with the de-rusted pulley just to see.

[KE4AVB]

I think you just found your problem and that it is the belt being a half inch short.

Belts being shorter than spec'ed length is something I have been fighting with my aftermarket vendor all year. That why I am changing after market belt suppliers; I was tired of the constant fight to get the right size.

On the that mower nearly all my suppliers are spec'ing 1/2" x 88-1/2" with the exception of one model of LR 121.

I just got through throwing 3 brand new belts away that were supposedly 103" long to find out they were only 101-3/4" even through the packaging was labeled 1/2 x 103. No wonder the mower was smoking belts when disengaged.

[38racing]

so I took another look on partstree. Besides my 9954140001 1996-08 there is a 954140001a 1997-12 (sic)and a 954140001b 1998-02. I doubt the 1a was produced until 2012 as many parts are NLA.
Anyway parts tree shows the 126520 superceded to 419271 which my AM says is 88 5/8 and replaces also the 144200 which my rotary of only 88" was supposed to replace. and the 1b belt is 124525 which my AM only offers the 4L890 as replacement. And the AM says this 89 " belt replaces the original spec of 126520. I guess I will measure the belt one more time and if it's 88 there's point of putting it back on.

[38racing]

got to just wonder. I looked through my belt list to see what I had. I have 7 brand new 754-0291a mtd belts that a dealer friend gave to me. Google says they are 1/2 x88. Just measured 2 of them. One about 87 1/2 , the other 87 1/4.
I found a diiferent used belt at 88 3/4 . mics at same width as the rotary but about .02 less thick so it should slip when de-clutched , maybe even slip in drive.

[38racing]

The used 88 3/4 comes to a stop with clutch. Also simple brake adjustment has it stopping now too. Now on to the deck repair. Belt on it measured a inch shorter than the spec belt.