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Technical Need Advice from the Gear Setup Experts; Ring Gear Pattern

Discussion in 'The Hokey Ass Message Board' started by crazycasey, Apr 6, 2020.


  1. You are correct Tommy, but those differences aren’t at play here...

    According to Montana 4x4 (Google search for “loose Dana carrier bearing bore”), carrier bearing bore damage is a common failure point on Dana 60 and 70 truck axles, and they have a fixture for reboring the housings. I’m sure that’s spendy...plus I’m in California.

    I went on Car-Part.com and found a half-dozen axles within’ 300 miles or so...$500 was the cheapest, all the way up to $850. One had 450k and another had 850k!?, though the few others didn’t specify mileage. Since this is my parts hauler, I’d also need to rent a truck to go get one of those. None of this leaves me feeling particularly warm and fuzzy about the “replace the housing” option.

    So, I’ve been slow to post measurements because I actually don’t have an outside micrometer that goes that big to measure my snap gauges (it will be here Sunday). The bearing races do fit snugly in the caps, but they don’t have any interference to speak of, except for some tension right at the parting line. This leads me to believe that maybe the caps have stretched, as is common I guess!? And when you pull the bearing race up into the cap, there’s clearance in the housing, but is that because the housing is worn out, or is that because the cap is stretched and I’m pulling the bearing out of contact with the housing?

    So, when I force the bearing race down into the housing bore with the cap off, I can no longer fit a 0.0015” feeler gauge (my smallest) anywhere around it. If I put the 0.0015” feeler gauge on the housing surface, and press the bearing race down on top of it, it’s very difficult to remove. So, while I don’t have any interference in the housing half of the bore, I also don’t have very much, if any, clearance...that is until you pull the race up into the (most likely) stretched cap.

    This leads me back to the idea of either replacing the caps, or surfacing down the ones I have. What I am struggling with about the folks telling me to replace the housing is that Strange and Mark Williams are recommending these caps for high-horsepower dragstrip cars, but they are only concerned with the diameter of the bore from bottom of housing to top of cap. They don’t say that you need to hone your housing after install. So there’s no way that a housing with those caps installed is going to be exactly concentric, which leads me to believe that the interference fit comes mostly from the top-down direction, and that they might intend the cap itself to provide some of the carrier control in the up and down direction (axle in the car).

    The spec for the bore (according to Strange) is 3.812” +/- 0.002”, and the bearing size is 3.815”. That means that a bore on the big end of the spec would only have 0.001” interference. That said, I’m really eager to get my 3-4” range outside mic, because according to my calipers, one of the set of bearings I have measured 3.8135” And the other measured 3.814”, but 0.001”-0.0015” error with calipers opened that wide is easy to get. Regardless, I can’t imagine I’m that far off if I can get new caps, or whip these ones back into shape, and I can always employ the Permatex for added peace of mind.


    Anyway, I really appreciate all the back and forth, and I appreciate you guys thinking through this with me. Considering that this thing was running and not making noise with this much slop in the carrier AND pinion (bores, caps, or both), and I can conceivably take away all the slop, introduce some interference in at least the top to bottom direction, and back it up with sleeve retainer, I think this thing will probably live a while...and I can look for a housing to replace this one down the road a lot easier when I get my van back on the road.

    Given the new information, and considering all the information, does anybody think that’s a seriously bad idea?
     
    Boneyard51 likes this.
  2. Thanks Eric. Hey, I know you were in the “surface the caps and see” camp before. After reading the info in my latest post, would you still agree?

    Sorry I’m so damn long-winded...
     
  3. Ericnova72
    Joined: May 1, 2007
    Posts: 589

    Ericnova72
    Member
    from Michigan

    Common for cast caps to stretch or break in high powered/heavy torque input applications, that's the main reason the MW and Strange caps exist, to be a strength upgrade more so than a common repair upgrade. HP and load is always trying to shove the carrier out the back of the housing, so the caps get stretched. Drivers side caps gets the biggest load, and this relates to MW selling the caps in singles rather than pairs, as most for a race axle the drivers side cap is the only one replaced since the passenger side cap doesn't see nearly as much load.

    Based on what you've posted I'd certainly investigate just reworking the stock caps, doesn't seem like you are trying to set this up as a drag or pulling truck axle that would call for the need for a steel cap deal.

    someone noted in an earlier post, if their is no vertical clearance in the bearing bore, and you get it fitted back down to no fore/aft clearance so that it is held on location, there is no real spin force trying to spin the bearing race, that is only going to happen if the bearing and rollers go bad. As another posted, bearing speed isn't real high either, just the same as front wheel bearings....1/4 to 1/3 of driveshaft speed/pinion bearing speed.

    Another way guys deal with adding strength is a rear girdle cover that has load bolts that contact and support the stock caps at the rearmost point of their arch. This avoids having to machine an aftermarket cap, and is works quite well on any rear loading Salisbury type axle housing such as the Dana, 12-bolt Chevy, 8.5/8.6 10-bolt, 8.8"Ford, etc.

    The rough trig calc I did was also using 3" as a bearing diameter, at an actual 3.812" diameter the amount the bore closes up for .005" removed at he mating point will be even less
     
    Last edited: May 16, 2020
    crazycasey likes this.
  4. Casey ,
    Your not long winded,,,,,,this was information that we needed .

    From what I read from it ,,,, I believe that Gimpy,,,EricNova,,,,and several others are on target .
    I believe if you rework the caps you will be okay.
    It would be hard to justify the extra expense of a new housing,,,,considering the intended use .
    And those bearing races sound on the small side,,,,,after you get your mic,,,you can tell for sure .
    Good luck,,,,,make sure you report the results,,,,,that will help the next guy here some day .

    Tommy
     
    crazycasey likes this.
  5. Boneyard51
    Joined: Dec 10, 2017
    Posts: 6,431

    Boneyard51
    Member

    I think that is what was recommended several times, once by me. One thing I want to point out is that they told you a spec that had a plus or minus .002 . That means that the machinist had four thousands to play with when making the part! This is the “ tolerances “ I was talking about earlier. Close counts. Lol








    Bones
     
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  6. Your right Bones ,

    Also,,,,I’m sorry I didn’t mention your name earlier when I was recalling all the guys recommending trueing up the caps .
    There were a lot of posts here,,,and I couldn’t remember everyone,,,,,sorry man .

    Tommy
     
    crazycasey likes this.
  7. Thanks Eric, that all makes a lot of sense, and I really appreciate you taking the time to type it all out.

    Thanks Tommy, I definitely will. I’ve been nervous posting here with a project from such an OT vehicle , and I’d hate to get “banned” from the HAMB after decades of contributing (even if I’m no longer an Alliance member), BUT, I do hope that the thread will ultimately be useful to some, an plan to update the results as I go. I really appreciate all of your insight.

    Bones, I hear you, and I’ve been leaning towards your recommendation from the beginning, BUT I had three other guys telling me I was headed down the wrong path, and so I needed to overthink it some more first.

    You’re right that +/- 0.002” is a pretty wide window, compound that with some margin of measuring error, and it’s arguable that some axles might have left Dana without any interference at all (possibly this one), but also, some axles fail far before their time. I’m guessing this one was a ticking time bomb, because the carrier practically fell out when I pulled the caps, and now I know to scrutinize things a LOT more closely before I put a bunch of time into them.

    I have become a pretty big believer in the modern anaerobic sealers in the last decade, and I do think that even with no interference, that a rear axle would probably hold together fine employing that sleeve retainer on all of the bearing races. And in this case I’m going to try and do a little bit better than that by reworking these caps!

    Thank you VERY much for helping me work through this problem mentally. I got pretty upset last night when people were recommending I scrap this housing and start from scratch.



    ***NOW, I want to ask you all one final time. I have no problem with the prospect of spending $100 on a pair of those Strange billet caps. I understand that most of you are saying I can probably get by with surfacing the stock caps, but they did stretch, and the Strange caps are supposed to be significantly stronger, plus $100 isn’t a lot of money for some added peace of mind. This rig is going to be roughly 8,000 lbs, and while it should have some increased mechanical advantage with the 4.10 gears (from 3.55), I can imagine the caps stretching again, and possibly more easily this time, since, from having stretched some already, the metal has arguably fatigued, right?

    I’m less interested in the Mark Williams caps just because they’re 2x the price (for a pair), and mostly because they’re going to take several days to get with the way shipping and logistics are going right now. Plus my crappy little mill will have a more difficult time getting good surface finish on tool steel. Though, to @Ericnova72’s earlier point, I suppose I could rework my NRGS cap, and just buy one of the Mark Williams caps...still, if I’m going to do it, and with the condition of my caps, I might as well buy a pair.

    To pose my question more simply, is there anything to lose, besides a $100 bill, in buying a pair of the Strange caps?
     
    Boneyard51 likes this.
  8. Strange makes a very good product,,,,,don’t hesitate to use them if you want new caps .

    Also,,,don’t worry about the OT part,,,,,,just keep it on a differential level .
    I don’t think Dana’s are off topic here .
    But,,,,keep all of the OT details out of the threads if possible .
    And besides,,,,at least you are trying .

    Tommy
     
    crazycasey likes this.
  9. One of these days I’ll get back on my ‘29 Roadster build thread; sadly I’ve sold all my Hemi stuff, and that’s the only HAMB-friendly car left in my stable these days.

    Thanks again Tommy, for everything. I think I want the peace of mind that $100 bill will afford me. I’ll post more details later for anybody who stumbles upon this thread.
     
  10. Ericnova72
    Joined: May 1, 2007
    Posts: 589

    Ericnova72
    Member
    from Michigan

    The Strange aluminum caps are meant to be used in applications that need shock loading resistance, like high rpm stick shift or transbreak launches. They are not meant to be a long term durability item, they are meant for something that has to take a power "hit" and give a little then spring back rather than shatter parts like ring gear teeth. Same reason they make drag race Pro gears that are softer but tougher material and not heat treated as hard, so they will give a little and not shatter teeth like a hard street gear.

    If I was going to replace caps on an application like you've got, 8000 lb vehicle and street mileage, it would be with the MW steel caps, not the Strange aluminum.
    Same reason there are aluminum main caps for some engines, like the 383-440 Mopar is one that comes to mind I've seen before, where a steel cap bolted down tight on a real high output deal would just break the main bulkheads out off the block....the aluminum cap is used to cushion and absorb the blow and not fail the block. Not something that is suitable for street driving at all, got to be torn down regularly and caps replaced when they begin to show signs of distress or just changed out on a schedule to prevent failure. Aluminum rods are the same way....main reason to use them now days is shock absorption, and not light weight. You can now get light steel rods nearly as light as the 3 times bulkier aluminum, and no fear of failure from work hardening after XX number of runs.
     
  11. Makes perfect sense Eric. Now your recommendation to reuse my stock caps makes more sense. Though, I am torn, and may still spring for the MW caps...
     
  12. Boneyard51
    Joined: Dec 10, 2017
    Posts: 6,431

    Boneyard51
    Member

    Rear end caps fail due to shock loads, namely drag racing, where they pop the clutch at 6000 rpm. That’s where you need extra strength. The caps are way stronger that the traction of your tires on a steady pull.
    I have a Dana 70 in a one ton truck with a four speed and a 428 cobra jet engine, that I pull a trailer weighing more than 15,000 lbs and that rear end housing and caps has Over 200,000 miles on them.
    Milling the new caps is going to be a little tricky and subject to error. If your milling machine has trouble with steel, it’s accuracy could be in question. The caps are going to be hard to measure how much to mill off. It will probably become a trial and error situation where you are going to have to chuck and uncheck several times, compounding the possibility of milling the mating surfaces a little off square with the bearing surfaces.
    Also after metal is cast and then made into a part, the initial stress that it is subjected to will “stretch” the metal a minute amount, after that it won’t stretch much more , unless subjected to a lot more stress. Kinda like a “ seasoned” engine block.
    To ease your mind, order the aftermarket caps, and if everything works out, your good to go. If you encounter problems... you still have the original ones to fall back on !








    Bones
     
  13. That’s certainly an interesting perspective, Bones. Hadn’t thought about the caps stretching a certain amount, and then stopping, but I guess it makes sense. I definitely get that the margin of error becomes greater the more you have to take off. I shouldn’t say my machine doesn’t do well in steel, it’s just that I’m a lot more confident in aluminum, being pretty new to machining. Figured I’d get close on the mill and then sneak up to the final spec on the surfacing plate, but maybe you’re right that it’s not worth the trouble. Also, the Mark Williams caps require you to tap the bosses in the housing deeper, and possibly to drill for the required length. That’s another potential hiccup, due to my advanced stages of axle assembly. Hmmm...

    The van has actually lost weight with all the work I’ve done to it, as it used to have a mobile office built in the back, a giant Oman genset, and a lot of plumbing equipment, but it does also have an excess 12,000 lbs of tow rating and I don’t want to be afraid to haul with it. We’re actually planning a cross-country move in the next couple years, and the plan is to pull an enclosed trailer with this van...decisions, decisions...
     
    Boneyard51 likes this.
  14. I’m about the cheapest guy I know, and I would find a better core.

    I do hope it works out for you.


    Sent from my iPhone using H.A.M.B.
     
  15. Thank you, I hope so too. If a wrecking yard would let you take an axle apart and measure the housing prior to purchase, I’d be right there with you, but driving 300 miles and spending $500+ dollars on an axle with 4x the mileage, hoping it’s going to be better seems like a non-starter. I’d be more interested in trying to have this housing machined, but I wouldn’t even know where to start with that.
     
  16. Sooooo...

    I’m a little bit embarrassed. Remember when I said that the carrier bearing races were supposed to be 3.815” OD!? Yeah, well, they’re actually supposed to be 3.8125”. And the spec for the bore is 3.812” +/- 0.002”. That means that the carrier bearing in a Dana 60 can have up to 0.0015” of clearance and still be in spec.

    I’m still glad I went through this exercise, as I discovered that my caps were stretched in the process, but it seems like my housing is actually right in spec. Looks like @Boneyard51 was exactly right when he said that on the Dana 60 “close counts“.

    After a lot of deliberation, I think I’m going to order the Mark Williams caps and I will try to document the process of installing them. As Bones said, if I screw that’s up, I still have my stock caps to fall back on. I’ll keep you guys posted.

    Thanks,

    Casey
     
    Boneyard51 likes this.
  17. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,233

    gimpyshotrods
    ALLIANCE MEMBER

    These things happen.
     
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  18. Boneyard51
    Joined: Dec 10, 2017
    Posts: 6,431

    Boneyard51
    Member

    I didn’t want to post, quickly, so thank you Gimpy! Anyone who hasn’t read a set of mikes wrong..... hasn’t read many! No need to be embarrassed! Shit happens! Lol. Anyone that has ever tried and hasn’t had question marks, actually hasn’t been ... there!






    Bones
     
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  19. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,233

    gimpyshotrods
    ALLIANCE MEMBER

    I just got done converting a carburetor for blower use, and then promptly over-tightened the fuel fitting, breaking the housing.

    If I had a dollar for every error, I'd own a house in San Francisco, with a garage full of finished hot rods.
     
    Last edited: May 19, 2020
  20. Yup it’s easy to do all right.


    Sent from my iPhone using H.A.M.B.
     
  21. I actually just wrote the darn spec down wrong...haha! So it’s more brain-fart than technical error. Story of my life!

    My new Fowler outside mic is what clued me in to the error. My previous measurements came from a pair of Harbor Freight calipers, and I knew they were going to be off. As I was trying to get a feel for the new mic on my bearing races, and expecting them to be 3.815”, I was definitely questioning the accuracy. When I looked up the actual spec again, it was surprisingly close. I’m still trying to get a feel for reading the tenths scale, but I’m measuring my NTN bearings at 3.8127”, and my Timkens at 3.8128”. The Timkens are definitely bigger than the NTN’s, because I’m repeating those measurements, going back and forth between the two, but I wonder if the 0.0002”-0.0003” variance I’m seeing is error, or if they’re actually a few tenths over-size?

    Either way, my previous statement stands that a housing bore CAN be in spec with at least a thou of clearance on the carrier bearing bore. I’ll try to get some accurate snap gauge measurements now with the caps torqued in place, just to judge how much they stretched. Figure it will be good practice while I’m waiting for parts.
     
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  22. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,233

    gimpyshotrods
    ALLIANCE MEMBER

    I look at every mistake I make as practice.

    That way, when it comes time to make it again, I can make the mistake better!
     
  23. So Gimpy ,
    You’re saying you have a garage full of finished hot rods ?
    Lol .

    Every time I mess up,,,it cost me a lot more than a dollar,,,LoL .
    I guess that is why I am always broke ,,,,maybe I need to farm out all of my repairs,,,,just to save me some money,,,lol .

    Tommy
     
    crazycasey likes this.
  24. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,233

    gimpyshotrods
    ALLIANCE MEMBER

    Other people's mistakes are always cheaper than mine!
     
  25. I wanted to revisit this thread so that it may be of some use to anyone who stumbles upon it. After 8 days of waiting, my USPS Priority Mail 3-day package from Mark Williams finally arrived (yay Covid-19). These replacement main caps would definitely be a tricky install without a mill and some decent tooling...I had that stuff and I still managed to screw it up, but I think it’s going to be fine.

    6F732873-E4CC-4B31-9F34-85B0B9C42AF9.jpeg

    The first step in installing the Mark Williams main caps is to ensure you have adequate threaded depth in the main cap retaining screw holes. It seems that most housings are drilled deep enough, and Mark Williams recommends the use of a bottoming tap (1/2”-13 on the Dana 60) to thread the hole as far as it will go. After tapping, and with the bolts threaded in by hand as far as they’ll go, you need to ensure that you have < 1-7/16” distance from the underside of the bolt head to the cap mating surface.

    AB25108D-4F31-43F3-A8E9-C210BE0CE7E4.jpeg

    At this point you can install the cap, torque to spec (85 lb-ft on the Dana 60), and measure your vertical clearance. I had roughly 0.063” extra material to remove on my caps, and not being super confident in my snap gauge measuring or machining abilities, I decided to remove 0.058” and then recheck my clearance.

    9DF8253C-6CCF-423D-AF61-3F6E60CA68DF.jpeg

    And, now, full of confidence, because repeated measuring agreed that I had removed EXACTLY 0.058”, I chucked up the cap a second time, and took another 0.005”...but somehow I actually took 0.0085”. The spec was +/- 0.002”, and I’m now 0.0015” under the lower limit, but more on that later...

    630CAC2A-17E6-48EA-A7CE-1F2A8F0A2E69.jpeg

    I did all my milling with a 2-1/2”x45° facemill; I had gone on a tooling buying spree back when I bought my mill, and this was the first time I’d actually used this facemill. I kept my depth of cut at 0.020” or under and my eBay carbide inserts left a beautiful surface finish. I think the reason I went over on my second attempt is because I have always touched off directly on my part, and in an effort to be more precise, I decided I would try touching off on paper. I should have practiced first. I think it’s also possible, maybe, that I didn’t deburr the part carefully enough, and there could have been an extra thou or so hanging me up in between the first and second set of measurements.

    F7A52459-9704-43EF-A475-1901CCB4C629.jpeg

    To make sure I removed material from the cap squarely, I used this nifty Starrett spindle square. The hair that it appears to be reading off of zero is parallax from the angle of the photo. This thing lets you get an oddly shaped part dead level. It’s one of my favorite tool purchases.

    79CF08C5-1A8E-43E0-A72A-6110822E2899.jpeg

    FF518BB1-43D5-4AFA-A1A5-83A9510ED9DD.jpeg

    My second cap worked out perfectly. By this point I was becoming very confident with my snap gauges. I measured the clearances on the second cap four times in a row within a ten-thousandth. My mic isn’t even that accurate, so, I was happy with the results. Again, I milled the cap in two steps, touching off on the part instead of on paper this time, and this time it landed exactly on the spec...twice. Then I took another half a thou off on the surface plate just so that the bearing interference would be snug. I bolted everything back together, double checked my backlash (in spec), double checked my pattern (which still looks better than anything I got on my setup bearings), and then I flipped the axle over to take a reading of the rotational resistance.

    25D676AB-18A4-44C9-B770-2210274AF130.jpeg

    My thinking was this; if having an extra 0.0015” of interference was going to deform the bearing race enough to cause an issue, I would be able to “see it” on my dial type inch-pound torque wrench. I had a dead consistent 50 in-lbs of rotational resistance, which is right in spec. Also, I figure that a bearing will wear in couple of thou, so I’m banking on the extra interference being a non-issue. Worst case scenario, I experience accelerated bearing wear, and I have to buy another cap and replace the carrier bearings sooner than I would otherwise need to. In the interest of calling this thing done, I’m going to take that chance. At least there’s not really any chance of it spinning and taking out the expensive parts.
     
    Last edited: May 29, 2020
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  26. Ericnova72
    Joined: May 1, 2007
    Posts: 589

    Ericnova72
    Member
    from Michigan

    Glad to see you got it worked out.
     
    crazycasey likes this.
  27. Thanks Eric. Your advice was really appreciated, and very helpful.
     

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