Difficulty getting 30-35 lbs of torque on Ruckstell Ring GearBolts

[henryford2]

Has anyone else had difficulty with the currently available Ruckstell ring gear bolts in getting the specified 30-35 lbs. of torque and aren't the washers suppose to be hardend as mentioned in the handbook? I have two styles of torque wrenches a beam and clicker ( I use one to check the other) these are not inexpensive Harbor Freight Tools. What am I doing wrong? Suggestions?

[Ruxstel24]

Joe, new ring gear ?
Did you chase the threads in it ?

[henryford2]

Threads in the ring gear are fine (hardened so tough to chase). The rear end has already been assembled and clearances set, this happened in the "final" steps of assembly.

[RajoRacer]

Yes, the washers should be hardened and I've never used a torque wrench on those bolts & I've got probably a couple dozen or more (+ my 5) Ruckstells under folks' T's running around the Greater Seattle-Tacoma area !

[speedytinc]

Generally not. Washers were grade 8 in my last set. Bought from Chaffins(hes the rux parts guy) Bolts were not black finished.(bare) Inferior copy bolts?? Only time I have had a problem was with the ring gear thread on a repop. Ring gear should be hard as the hubs of H#!!. you will shatter that tap.
A small grinding stone is your only chance to remove the bur. Either way, pre check the bolts in the gear.

[speedytinc]

Threads in the ring gear are fine (hardened so tough to chase). The rear end has already been assembled and clearances set, this happened in the "final" steps of assembly.

Ok so go back a step. Didnt you have it all apart 5 or 6 times already to get the clearances right?

[henryford2]

Rear end has been together and apart a number of time to set the clearance. The bolts/washers came from the current vendors. I'm going to run to the hardware store and pickup some grade 8 flat washers, and re use one of the better old bolts to get this rear end together.

[speedytinc]

Rear end has been together and apart a number of time to set the clearance. The bolts/washers came from the current vendors. I'm going to run to the hardware store and pickup some grade 8 flat washers, and re use one of the better old bolts to get this rear end together.

Sure, that might work if the gear thread isnt bad. I assume you lubed the bolts before installing. Hope the other bolts didnt have an issue. You will know when you replace those washers.

[henryford2]

wish i had read this before today http://www.mtfca.com/discus/messages/70 ... 1505355710. Those are grade 8 washers mine are not? Threads were oiled, threads in ring gear are good, I'll follow Dan's advise and shoot for the 20 ft. lbs. of torque

[John E. Guitar]

I think the 30-35lb.ft. is for dry threads.

[henryford2]

Thanks everyone, I did not intentionally oil the threads, but they were oily from all the handling and assembly in setting up the clearances. I'll make sure they're dry and use Original Smith's method to tighten them (I believe Stan Howe also avoided the use of a torque wrench). I'll take blame for the not getting torque issue, but no way are the washers that were sent with the bolts hardened!

[TonyB]

On a Ruckstell axle with mainly new parts from Chaffins several of the threads on the bolts failed at 30 lbs ft. I spoke with Dave and he replaced the bolts with new ones with no problems. He mentioned that the bolts were treated in batches of about 1000 and some don’t make it. Annoying but not much can be done without considerable expense.I guess you pays your money and takes your choice.
So yes they can and do fail.

[speedytinc]

On a Ruckstell axle with mainly new parts from Chaffins several of the threads on the bolts failed at 30 lbs ft. I spoke with Dave and he replaced the bolts with new ones with no problems. He mentioned that the bolts were treated in batches of about 1000 and some don’t make it. Annoying but not much can be done without considerable expense.I guess you pays your money and takes your choice.
So yes they can and do fail.

Well, thats a disappointment. I have had a high level of satisfaction & trust in their rux parts. What you gonna do?
They make most/all the new rux parts all the vendors sell.

[Scott_Conger]

I do not doubt what Tony said about being told "some don't make it". That said, to make a statement like this to a customer is utterly ridiculous. Either the steel is not to the spec, SOME of the steel in the lot is not to spec (wildly irresponsible on the bolt manufacturer) or the heat treat process is completely out of control. Utterly ridiculous or not, it is a process which should not continue without a complete Root Cause and Corrective Analysis performed by the supplier of the bolts. It would certainly happen if I was the vendor who's name/reputation was on them for public consumption. That product line would cease until it was fixed or if necessary, another supplier was qualified as a vendor. I know it is hard to get shops to do small jobs now, but this is not a malformed trim piece or some other sort of bling...it is a key part of a driveline.

I have great admiration and respect for this supplier and am the LAST person to complain, but honestly in this instance, selling hardened bolts that are a total crapshoot is a really bad thing.

[Dan McEachern]

Regardless of everything above, expecting a 5/16-24 bolt to torque at 30-35 ft-lbs is just plain incorrect in my opinion. I'll assume that Chaffins bolts are made from a proper alloy like 8640 or 4340 and heat treated accordingly, but even ARP 190KSI 5/16-24 bolt recommended torque is 28 ft-lbs and that is using ARP thread lube, and this is for a very high quality fastener.
You should all make your own conclusions from this.

[TonyB]

Fascinating.
This could explain why I see so many damaged threads on existing bolts, which I always buy new. They are relatively expensive but I keep some on hand in case one fails. The last time was at a customers shop so we complained and Dave replaced them immediately.
I guess we should stop at 25 !

[henryford2]

With my background and experience I should have been skeptical of the 35 lb. ft. of torque on the bolts. This was my first Ruckstell build and I was using the yellow book as the "bible" during the rebuild. I did not intentionally oil the threads, but I didn't ensure that they were dry either. Fortunately I had just started the final torquing of the bolts and the very first one failed trying to achieve the stated torque. What irks me the most was the soft washers that were supplied with the bolts. Why use something other than the same grade washer as the bolt? A trip to the hardware store fixed that. I'll know better in the future!

[Scott_Conger]

Dan

I agree with you regarding torque amount. That is a lot of torque for that size fastener, but I do not know what the fastener is rated at and prevailing wisdom (the manual) has for years advised that torque. I'm pretty sure that this manual was written primarily by the retail vendor of the bolts, so it is not a stretch for the average guy to "follow the manual" and expect success.

what I find troubling is that "some fail" and that is and has apparently been the default answer to bolt failure at a torque perhaps erroneously called for in the MTFCA manual. If "some fail" then I would either specify a MAX torque to apply to the bolt and include it with the product, or work with the actual bolt supplier to achieve more uniformity in the product.

[Mark Chaffin]

Hi Joe! Sorry to hear you are still having difficulty with your Ruckstell build. I'm must say I am bothered by the picture of the ring gear bolt and washer shown in your post. The bolt appears to have a black oxide finish and the washer is surely not a Grade 8. I'm not sure where you obtained these bolts and washers as they do not appear to be ours. Below is a picture of our P128 bolt and washer set from our most recent (2019) production run as well as the Heat Treat Certification.

Furthermore, the picture of the bolt with the damaged threads appears to have been cause by excessive force and / or an alignment issue with the ring gear and Ruckstell parts when mated together. We have found original Ruckstell part tolerances do vary from part to part and were not held to today's tight tolerances. In contrast, our Ruckstell parts are CNC machined and held to a tight tolerance. When using our Ruckstell parts with original Ruckstell parts, we have heard of customer's experiencing interference issues. However, this is rarely the case. To verify our tolerances were correct, we randomly selected and assembled the parts in question (P159 Differential Bell Housing, P93 Internal Ring Gear, P139 Bronze Thrust Plate and Ring Gear) using our P128 Ring Gear Bolt Set. We did so, without installing the Grade 8 washers to ensure the bolts seated properly without interference from the step on the shank above the threads. We were able to tighten the bolts by hand without any interference.

Lastly, as mentioned by dad in the prior posting, the recommended assembly torque value is 25 lbs. Yes, this is in conflict with the 35 lbs. as indicated in the Ruckstell Manual. Where this prior recommendation came from is a mystery as neither Ford or Ruckstell cite torque values. Hopefully, the Ruckstell Manual can be updated to reflect this change before being printed again in the future.

In closing, I hope this helped answer any questions you and others have regarding the likely cause of the problem and the quality of parts we manufacture. Furthermore, I have directed Dave to send you a P128 Ring Gear Bolt and Washer Set free of charge to help you complete your Ruckstell build.

[henryford2]

Mark thank you for the replacement bolts and washers. Yes the assembly of this Ruckstell has been a struggle. I absolutely understand the challenges of mating 100 year old parts that were probably ganged drilled with those done today on CNC equipment. Specifically, I struggled in getting the assembly bolted together. The bronze thrust plate, P159 Bell housing and bolts were purchased from either Langs’ or directly from you. The bolts thread easily into the ring gear through the P159, likewise no issues then going through the P93. It’s only when I tried to get them to enter through the P139 thrust plate inevitably two or three won't enter the ring gear and others feel as if they are meeting some resistance on their way through the assembly. Not tightening them up leaving them loose, tapping the assembly with a brass hammer, etc., nothing seems to work.  The bolts show a sign of a struggle when you remove them. I believe the P139 was drilled with a 21/64 drill (although the drill will not go all the way through and I had to run a 21/64 drill through it), a letter P drill is too small. I replaced the bolts with old bolts I had here, no problems went right in. You can tell by the pictures of the bolts that they are contacting the holes as they enter through the parts. I miked both sets of bolts and they are within a few thousandths of one another (the originals are slightly smaller). Have no idea what's going on. Threads not concentric to the body of the bolt? I’ve already run a 21/64 drill through the P139, if I need to run a drill through the P159 what size drill would you suggest since the bolt does have 2 different shank diameters? No impact wrench was used, the largest tool used was an 8” combination box wrench and a short handled 3/8 ratchet, so the bolts were never pounded or driven into the assembly. Thanks again

[Mark Chaffin]

Based upon the striation marks visible on the P93, it is the likely culprit. Since is appears you are having interference with only two of the ten bolts, I would relieve those two holes in the P93 by drilling them out with a slightly larger drill to provide the clearance you need. Be sure to mark the orientation of the of the parts in relation to one another for reassembly. Hope this helps. The P128 Bolt and Washer set just went out USPO Priority. You should receive them soon.

[henryford2]

Mark, I'm all showered up and in my PJ's for the night so the parts aren't easily at hand. I had no problems with the bolts going through the P93 and the P159 into the ring gear, but if the holes in the P139 are off location (in relation to the center line) it would throw the bolt towards one direction or another causing the bolt to rub against the P93? Also the P93 is the internal ring gear and I'm assuming has some hardness making it difficult to drill? Thanks again, Joe

[henryford2]

Got the replacement bolts today. Thank you again. In comparing the old to the new, they do have a different finish and machining marks, so either a different vendor or different batch? The one thing that drew my attention to the new bolts is that the shank has an "undercut" at the start of the fillet under the head. In my experience if the bolt is in a relatively high stress condition I would have avoided the undercut and had the fillet tangent to the shank (just my humble opinion). Lastly if I continue to encounter issues bolting the assembly together can I safely open up the holes in the P-159 to .3230 (letter drill P) which is considered a "close fit" hole clearance for a 5/16 bolt? I believe they may have been originally drilled with a "O" size drill? Drilling the P-93 is not an option, it is hardened. Thanks again for the help!