Busted bolts in rear belt pully - Harley Forum

03fxst · #1 08-07-2007, 09:22 AM

Hey gang
It's not a trans clutch or primary issue but I figure it's close enough. Had a scary incident on the weekend. A slight unusual ticking noise that I could not isolate kept getting worse. It was more pronounced as I dipped the bike to the left and went away under constant steady torque. I was close to my stop for the night so I kept it steady as best I could until I got there. I found the ticking was the washers from the 7/16 bolts holding the rear drive pully to the hub. All five had come loose, or so I thought. I tried to tighten and could only get a solid hold on two. This was a Friday night more than four hours from home. Following morning I rode slow and easy to a nearby dealer where I got great service. Tech showed me that three bolts had broken at the point where they leave the pully and enter the hub. He also showed me the collars on the bolts were too short. He replaced with some from a nearby truck supply shop. Those collars went all the way through the pully and then the threaded portion engaged the hub. Anyone ever had, heard of this problem. The bolts are HD Chrome replacement bolts. When I got home I checked the stock bolts, same short collar.

#2 08-07-2007, 04:07 PM

Man, that is a little scary. I'm glad it didn't cause you to have an accident. Thanks for calling that to our attention. I have found that many chromed bolts are quite soft (for ease of polishing I assume) and have replaced a few with grade 8 bolts from the local farm supply. Enjoy your Summer and ride safe. The wife and I went for a nice ride on some nice backroads that I discovered, then retreated from the heat for a while.

#3 08-07-2007, 11:37 PM

Bummer. I wonder if you got a bad set of bolts? I will not use chrome bolts on any part of the bike that could cause major problems if a bolt broke. Chrome is soft. The chrome bolts that I purchased at the Harley dealer are crap. I swapped out alot of stock bolts and replaced with ones from the Hardware store.

94flhtcu · #4 08-08-2007, 01:10 AM

Most important to me, is where does the bolt's shoulder end? The shoulder should go thru the pulley, and slightly into the hub. In other words, there should be no threads of the bolt inside the pulley. That's the weakest spot of the bolt supporting the highest part of the load. Add a few horses, do a couple of burn outs, and this stuff comes to the top real quick.

03fxst · #5 08-08-2007, 09:23 AM

Hey 94
That's the problem. The collar only goes half way through the pully. The rest is threaded and that includes the break point on these three bolts which happened at the point where the hub and pully meet. The three I picked up from the truck parts store have collars that go into the hub which does have room for a collar. I'm going to get two more. There is no question these HD bolts are wrong. As I mentioned earlier chrome or no chrome the bolts are wrong because I compared them to my stock bolts and they also have a collar that goes only half way through the pully. I'm no engineer but that seems to be a bad idea.

94flhtcu · #6 08-08-2007, 11:04 AM

From what I've learned about hardware, you and I are right. In the equipment repair industry, we call these "reamer screws". Not everyone calls them this, though, and Im not sure of the correct terminology. Just watch the depth of the bolt, so it doesn't ruin the 1st thread in the hole.

But, cool, you know what happened and what to do. I'll be checking the wife's heritage.

The first thing I did to my flh was to redirect the crankcase vent. I got the tube kit from hd, and the banjo bolts were a joke. I had barely started one and it WRUNG OFF in the head. Great. Wasn't cross threaded or nothin. Jumped in the truck with two grade 8, 1/2" bolts and went to my buds. I had him cut me a couple similar to the hd ones, and thier still on it today. Overall, I haven't run into any other issues on hd's hardware. Good luck!

#7 08-15-2007, 04:52 PM

The same thing has happened to my 03 FXD. I had this repaired by the local shop. I had 3 bolts sheer and the other 2 were close behind. About 200 miles after the bike was repaired, I had 2 of the new bolts sheer off and 2 more were backing out. The bike is back at the shop and they have no clue why the bolts are backing out. Does any one have any ideas why this is happening? Both sets of bolts were grade 8.

94flhtcu · #8 08-16-2007, 12:22 PM

Bolts which are cleaned correctly, locktite and torqued properly should not back out. I'd suspect something wasn't done completely or correctly. Having said that, I can also tell you this... never say never. Seems like the impossible happens easily on mechanical assemblies, with no explanation.