need info ASAP - detroit locker

[Fantom]

detroit locker - rebuild .....sort of.....

Hi guys,
Here is what I need (then I'll get into what happened):
I need to know the size of the bolts that hold the Detroit Locker together for the BJ60. This is in reference to the 6 or so screws that hold the pillow-block and cap on the locker (allen head looks like a 6mm allen head bolt). I need the length, the thread and diameter of the screws.
Can someone who has access to one, please text me the info at 604.803.3506 - Thank you!

Now for the what:
I finally had a chance to look at my truck and do some preventative maintanance to it. Some of you know I had a small incident at work last year and have been somewhat limited in what I could do. Normally, at the end of the wheeling season (or at least when the weather gets worse) I do a final check over the truck of everything that moves and can break and cause issues. Last year I couldn't do this.
Now I finally had the opportunity to do it, which resulted in a front end rebuild (water damage and rust), and just as I wa about to close everything up..... I decided to change the oil in the back diff .... at 7pm ..... I unscrewed the drin plug, the oil looked a little dirty but not too bad, no water damage, and what is that stuck to the magnet........

oh, it's a bolt head ..... allen key, bolt head...... ah s***!.....
I took the filler bolt out and shining the flashlight into the tiny hole I noticed that at least 3 visible bolts that hold the detroit locker together have come loose and are currently touching the bearing housing. So the truck is parked.

Sopel was kind enough to lend me his, I have to go to work tomorrow and Saturday, for more hours then I care to mention and will not have time to gut the rear end. I need to know the size of the bolts because I will tear it apart on Sunday and try to fix it, I can get bolts from my work on Friday and Saturday - help!
Call me, text me, send me smoke signals, I just need info.

Thanks!

.....stupid detroit.....buy selectable lockers!

 

[Glenn-BJ74]

so sorry to hear of your Detroit woes - but your truck has served you well and there comes point when ...................well, you know the rest.

I wish you a speedy repair

 

[Glenn-BJ74]

are these the Allen head screws - they look like like 1/4" - just a guess

 

[Glenn-BJ74]

might be a hard to get cap screw. The Detroit install manual says (no help on size)

Step 11e Insert the long socket-head cap screw (in plastic bag) through the differential plainside
cover and thread into differential housing. The end of the screw will engage the hole in the
spacer pin thus holding it in place. Torque the screw to 23-25 ft.-Ibs. (31-34Nm). Note: this
screw has a thread locking patch pre-applied to it. If for any reason it is removed after
installation, a thread locking compound must be re-applied before reassembly.

 

[Fantom]

Ok, another long day.....
So I got pissed off and after work took the rear cover off the rear differential, and I saw 4 of the 6 screws had backed out, the one I removed and installed again (for the pillow block) stayed in place and one was missing entirely (that's the head I found attached to the magnet).
Hoping....praying...they just came loose, I tried moving them and found all of them were broken (except the pillow block one).
Off come the wheels, the drums, the axles, the drieshaft, the differential housing and onto the work bench. 4 bolts are sheared right at the main housing, one is sheared at alomst flush with the housing cover and one is still holding strong - beyond amazing that it survived.
Sadly, there is little to do here but take the assembly apart, losing the preload on the bearings, and seeing if I can deal with the situation. Got it all apart, locker and everything and 4 of the 6 bolts are below the main housing, and stuck. I managed to get the other one that was sticking out unscrewed and found no sign of old thread lock of any kind. The housing was still perfectly aligned so it's not that it sheared the bolts in a rotational force, it was captive between the bearings which were preloaded by Steve's guy and have been working fine (by the way the wear on the gear is barely visible so he aligned them really well!). I have no explanation for 5 of the 6 bolts breaking.

And for the record, 5/16" 18TPI 1.5" bolts, GRD 8 or 10.

Solutions:
get a new locker.....time, money, and I honestly will never buy a full time locker again.....even to replace the one that's broken.
get a new housing......time, money (no clue how much), having to get new bearings for the new housings, resetting everything.....grrrr.
clock the cover 15 degrees, drill and tap 6 new holes ......hmmmm, I have everything to do that, and if I fail, I am exaclty at the same place I was at before I started, only I waste 1/2 a day. Decisions, decisions......
pics: as I found it, the broken off bolts, and the housing with the broken bolts.

 

[Fantom]

more pics: the long broken off bolt when slowly taking the locker apart. Those springs have a lot of power, be careful if you ever take one apart.
The main housing, the little orange stuff on the bottom is silicone, I am not sure why it is there, I did use silicone on one of the trips where I have to replace the axle and make a gasket on the side of the highway but I don't know why it all moved in into the inside of the locker......odd
and the close up to the below the surface broken bolts.

 

[Fantom]

Glenn, I know I use my truck off road a lot and am not easy on it when I do but that is still pretty weird damage to happen and considering the rest of the gears and inside of the locker look great - it makes not sense.
I don't know, is 6 years a lot out of a locker? I am not running a very large horse power machine with tons of torque and only have 33" tires and after all the hardest trails that truck sees is stuff like Roche, Whipsaw, MacKenzie, etc - we are not talking about king of the hammers trails here. I would have expected a little better.

I'm too tired to edit that and make it sound better. hopefully tomorrow will suck less.

 

[Glenn-BJ74]

There are reports of those 5/16" cap screws backing off on other Detroit's on the net, Possibly the factory thread locker is inadequate (the install manual says they come in a bag with thread locker on them) assuming proper torque and sequencing. Was it red locktite was there enough on the threads, were they clean surfaces?

Diffs should last the life of the vehicle and Detroit's have a good reputation, except for the cap screw issue.

Detroit's are made by Eaton based in Cleveland, Ohio. which is a long way from Japan or Oz

 

[Fantom]

The screw that I was able to remove (the one that had enough meat on it to grab with vice-grips) looked clean, too clean to have lock-tite on it at all. It did not come out easy but after looking very closely on the threads they were all a little stretched out, so that would explain it.
Now the issue is not that they backed out - because they didn't, they snapped, almost as if they were torqued too much. Ironically, the only one that didn't was the one I put it.
Once again, it goes to show, DO IT YOURSELF! you know it will be done right, or at least if you screw it up you can slap yourself.
So the new setup will be leaving both housings where they are, and drilling additional holes in between the old ones, and this time tapping them to an M8 screw size - the thread count is a little finer but not as bad as a fine thread imperial. The cap screws I got are high grade steel, we use them on CNC machines all the time and I have seen them stand up to amazing damage.

 

[BC40]

Sucks that happened. Makes me wonder about mine. Haven't looked at it since it went in 8 or 10 years ago.

Good plan on the fix, those hardened bolts would be tough to remove. As for redrilling the housing, so the plan is to end up with one extra fastner; the long bolt for the center pin block being re-used? I'd likely try to use bigger than 8mm, either 3/8 fine or 10mm if possible .

 

[Fantom]

The housing will not allow for anything bigger, and it is the same size as the existing 5/16 bolts but a slighlty finer thread for added strenght. The end result will be an additional fastner but I think that is overkill, I am very strongly leaning towards one of two culprits:
either substandard bolts (bad batch, lower grade, made in kazakistan....)
or over torqued, and with time, vibration and repeaded shock of the locker "snapping" and shifting teeth, it popped the bolts right off. You can actually see the threads are stretched.
I think that if it was orignally installed with proper thread lock, torqued to the bolt's specifications and they were good quality, it would have worked perfectly fine and never came off.

You should at least pop the rear cover off to see if everything is still in place.

 

[ForealBoreal]

Mat, is your truck 24v?
Sorry to hear about your locker.
I know its money but have you considered going with some jdm60 series locked axles or retrofitting some 80 series e locking thirds?
The other route is arb?

 

[sailor]

a Canadian BJ60 is 12v.

 

[Fantom]

I have considered a lot of things, as a matter of fact I have a set of JDM axles, front and rear, with cable lockers, thanks to Sopel, in some what of a rusted condition and in need of a rebuild, but at a price I could not pass up, once again, thank you Sopel.
I also have a rust free truck I have some what started, and need an engine for, so this is a repair to just get it to run again and maybe get a trip or two out of. I do need a truck to wheel to at least come up with some wheeling stories and good photos, since very few people are submitting stuff to the magazine! hint.....hint.....

 

[sailor]

Lance and I have a metric shi* load of photos from the epic moab trip- you should convince him to write up a trip report...

 

[Fantom]

ok, side track, we are trying to keep the magazine BC based. Yes, BC guys go to the US and do trips, and usually to destinations that have already had 50 magazines cover over 100 times over. We are trying to showcase BC, and the literally millions of trails we have in this province alone! Us destinations are cool and different and seem exotic to us, but honestly, it's been covered a lot, we do have a lot of cool stuff here too. With that said we are not entirely opposed to something out of province but it would have to be off the beaten path. Something a little different than what every other magazine has already written about - and I don't mean you and Lance dressing up in women's clothing for the duration of the trip - because that is just wrong....different.....but wrong!

 

[sailor]

I can understand your confusion if this sets your standard for masculine fashion...

 

[ForealBoreal]

I have considered a lot of things, as a matter of fact I have a set of JDM axles, front and rear, with cable lockers, thanks to Sopel, in some what of a rusted condition and in need of a rebuild, but at a price I could not pass up, once again, thank you Sopel.
I also have a rust free truck I have some what started, and need an engine for, so this is a repair to just get it to run again and maybe get a trip or two out of. I do need a truck to wheel to at least come up with some wheeling stories and good photos, since very few people are submitting stuff to the magazine! hint.....hint.....

Cool,
Swap a newer 3b into it? When do you expect to have this rig done?

 

[crawlin cruiser]

Mat I doubt it's the offraod that ruined your Detroit. It's the day in day out of pavement. Barking tires around corners and such. I know you more than anyone here goes out on trips but to me daily driving will kill it.

 

[Fantom]

I do agree with you Dan. City driving is tough on fully time locked differentials, axles and tires. This is where full time locked differentials suck, and I will never do that again. Even in off road application there are many times I would have had an easier time with the locker turned off. It's impossible to prove what killed it in the end, in off-road use you get random, more instant shock from obstacles and on average we drive the vehicles harder than we do in the city. In city use you get no give from mud and soft dirt, and the stress is almost sustained for the duration of driving. Flip a coin.

ForealBoreal, .....it will be done .....eventually and have to find the engine before I do anything else. Toyota, used, diesel drivetrain is over priced. Last time I found a guy selling a 13BT, 5 speed, transfer that was 20 years old, withunder 200,000kms, for $8,000. I'm sorry, I'm not about to pay that much money for an setup that has no history, for all I know it was treated like crap its entire life and I'll get 50,000kms out of it. The used market value for these engines has been hiked up way too much. I can get an entire truck, with a Cummins diesel with under 300,000kms for $3-5,000 - that's an entire truck. I get my engine, wiring, and whatever else, sell the body, frame and axles and I'm done. I am seriously looking at going that direction now. We'll see what happens.