[johnbryanpeters]

The swingarm pivot axle on my Heckler seems determined to worm its way out of its clamps. The cap unscrews and the shaft migrates right or left.

I set it up again today to spec - torque pivot cap to 70 in-lb (how the hell am I supposed to do that prior to tightening at least one pinch bolt?), torque swing arm pinch bolts to 125 in-lb. We'll see whether it stays.

Anyone else have problems with the axle coming loose?

 

[davep]

If this continues, put a thin film of loc-tite on the clamping surfaces. A cylindrical retaining compound like loctite 608 would be best, but others will work.

I use this (608) on any and all pivot axles (bearing contact)and press fit assemblies (bearings etc) on all my suspension frames. Prevents metal to metal contact and corosion as well as movement/creaking of these parts.

 

[SuPaFlY]

happened to me as well. Definately, a part that you loctite while building. Makes life easier on the trail not having to look for the bolt to get home.

 

[johnbryanpeters]

After cleaning everything, reassembling and torqueing everything to spec, it has held together well until today, when I discovered that a pinch bolt cap had sheared off and it's loose as a goose.

Two week wait predicted for replacement bolt (specially designed head) and its hardened steel washer to arrive, sigh...

 

[Bootboiler]

Hi John,

Are you still having Pivot Bolt Issues? I have broken 4 pivot bolts, and in one case it stripped out my swing-arm. Santa Cruz replaced that part, and LBS put it on without charge, but the newest bolts are short, and only use about half the available threads.

Got a call in to see if they will give me longer bolts.

 

[johnbryanpeters]

I bought some stainless metric cap screws at a hardware store and they're working. I don't like the ones provided by Santa Cruz.

I wound up buying a full kit from SC - pivot axle, end cap, the pinch bolts and the fiddly washers that go under the bolt heads.

I find that if I scrupulously clean everything before torquing things up it seems to hold together.

BTW, if you have one and a half thread diameters of engagement, you have all the strength available - I seem to recall that the pinch bolts are 5mm, which means that if they're threaded in 7.5 or 8 mm (about 5/16") it's enough.

 

[johnbryanpeters]

Hi John,

Are you still having Pivot Bolt Issues? I have broken 4 pivot bolts, and in one case it stripped out my swing-arm. Santa Cruz replaced that part, and LBS put it on without charge, but the newest bolts are short, and only use about half the available threads.

Got a call in to see if they will give me longer bolts.

A bolt only has to screw in about one and a half thread diameters to develop all the strength you'll ever get from the threads.

I have come to the conclusion that the PDF on the Heckler site telling how to assemble the pivot has some major typos. In particular, they tell you to tighten the pivot cap to 70 in-lb and the pinch bolts to 125 in-lb.

They cited the wrong torque. The pivot cap is hardened with 10 mm D threads; the pinch bolts are 6 mm D stainless. If you look at the parts list in the detailed drawings, it specifies 65 in-lb for the 6 mm pinch bolts and 70 for the cap.

I'm now using 125 in-lb for the cap and 70 in-lb for the pinch bolts. I would dearly like to discuss this with their engineers and shop monkies.

 

[C.P.]

Had a heckler 5 for a while, and JBP, I tried everything, in the end the only thing that worked was a dab of locktite on the hardware...

 

[dsb18292]

If you continue to have issues, put a call into SC. After my 4th pinch bolt snapped, several loosening episodes, creaking, etc, the threads finally pulled out of the swingarm. SC warrantied the swingarm to the new type w/o pinchbolts. The pinch bolts are a well know problem. Some get away with the stock setup. Others have issues. Sounds like SC is taking care of the ones that come down with problems.

 

[SuPaFlY]

I hate to say, but under some instances, torque specs are retarded. I have had a few issues with the main pivots coming loose on hecklers, Blue loctite, and more Torque on the main pivot always works. Torque specs are to keep moose knockle wrenches from destroying parts and blaming the manufacturers. Tighten her up more, and torque the bearing pinch bolts. This will limit the amount of drag on your bearings while keeping you pivot nice and tight. ALso, ditch the stock bolts, companies chince out on high quality bolts for price. Get some high strength heat treated bolts, they wont pop, can get longer threadings and cut to length, and are FAR higher in psi and tensile strength.

 

[dsb18292]

Honestly the SC stock bolts seemed to hold up the best of the ones I tried, which included some high grade McMaster Carr bolts.

The new design seems to do pretty well. About the only complaint I have is that the axle and the locking allen turn the same direction, so you can actually unthread the axle before the loctite on the locking allen breaks. It is similar to a maxle (like the boxxer DH), but they release the locking allen from the other side so it is tightening the axle as it breaks free.

 

[johnbryanpeters]

Just went another round after threads in swing arm for one pinch bolt stripped out. Installed a helical insert last night.

 

[gawdodirt]

Just went another round after threads in swing arm for one pinch bolt stripped out. Installed a helical insert last night.

Did you mean a "Heli-Coil" insert? No biggie, but it helps if someone else goes to buy one. I know, it's like "Kleenex," a generic term.
I read the past post about the thread engagement depth. Yes, you're right that you get no more strength than 1.5 times the diameter, but the depth does help to spread the shear force onto more threads to help avoid a stripped threaded hole. Mine had broken off the head of the pinch bolt on my 2010 Heckler. The threads were still in great shape. My thought was to drill it through and use a nylock nut on the other side, if they were damaged.

GD

 

[johnbryanpeters]

I was deliberately using the generic term. It happens I was using FNL EZ-LOKs since that's what I found locally.

Some of the cap screws that Santa Cruz has provided have been very odd. The socket goes so deep that it almost reaches the shoulder, leaving inadequate meat to prevent shearing.

My typical failure has been that the head shears off, after which I drill, using a centering bushing, then use an easy-out to remove the shaft. I have thought of using a through bolt and a nut, but it's bulky and inelegant.

 

[gawdodirt]

I was deliberately using the generic term. It happens I was using FNL EZ-LOKs since that's what I found locally.

Some of the cap screws that Santa Cruz has provided have been very odd. The socket goes so deep that it almost reaches the shoulder, leaving inadequate meat to prevent shearing.

My typical failure has been that the head shears off, after which I drill, using a centering bushing, then use an easy-out to remove the shaft. I have thought of using a through bolt and a nut, but it's bulky and inelegant.

It's often easier to extract using a left hand drill bit. I did and it literally screwed itself out. I had no issues punching right down the center first time. The through bolt and nut would afford greater clamp load, since you can then use hardened nut and bolt. Similar to going from cap screws on con rods to through bolts.


GD