axles

hauss · #1 (**permalink**) 07-22-2019, 12:39 AM

Looks like I may need a new drivers side axle for my 2013 backdraft. All I know is my wheel will rotate about 3/4" without moving the flange on the diff. Axle bolt is tight and so are the allen bolts. Not sure if this is normal or not.I have the new style axles because I have a bolt on the end rather than a nut.If someone could tell me where to purchase a new axle cheaper than from iconic parts I would be most grateful.Trying to save a little money I would even rebuild if possible.

eschaider · #2 (**permalink**) 07-22-2019, 05:49 PM

That seems like it is nearing the upper limits of acceptability.

The clearance you are experiencing is a combination of the slop in the splines and side gears (usually minimal) and the backlash on the ring gear. You might want to pull the rear cover and measure your backlash and if it is high set it to the low limit for your rear end. That will measurably reduce the slop you are detecting.

When you go low on backlash be sure to check the backlash at four positions on the ring gear that are 90˚ apart. If you discover tight spots back off a bit until they do not present an issue.

Another thing you want to be sensitive to is decreased backlash produces increased oil shear issues and elevated oil temperatures. If you start to loose oil out the breather on the housing (and you're filled to the proper level) you will require either an oil cooler or an increased backlash on the R&P.

While you are in there you might also want to check your pinion depth against the Master Housing Depth (MHD) spec for your rear end.

Ed

Gaz64 · #3 (**permalink**) 07-22-2019, 06:52 PM

I think the op is talking about slop from the wheel to the diff output flange, which is axle cv joint or universal joint slop in this one output driveshaft, not diff internal backlash.

Gary

hauss · #4 (**permalink**) 07-23-2019, 12:05 AM

Does anyone know what axle is in the car, or is the backdraft the only axle I am able to purchase?

hauss · #5 (**permalink**) 07-23-2019, 12:09 AM

I was hoping mr.cashburn could shed some light on the subject.

eschaider · #6 (**permalink**) 07-23-2019, 12:12 AM

Quote:

Originally Posted by Gaz64

I think the op is talking about slop from the wheel to the diff output flange, which is axle cv joint or universal joint slop in this one output driveshaft, not diff internal backlash.

Gary

You're right Gary. I misread the original post. That is not ring gear backlash, that is a broken part somewhere between the drive wheel and the differential side gear. My guess would be a broken axle. Disassembly will tell the story very quickly.

Ed

Gaz64 · #7 (**permalink**) 07-23-2019, 01:18 AM

Quote:

Originally Posted by eschaider

You're right Gary. I misread the original post. That is not ring gear backlash, that is a broken part somewhere between the drive wheel and the differential side gear. My guess would be a broken axle. Disassembly will tell the story very quickly.

Ed

Yes, I know, I had to read the original a few times to get it in my head.

It would good to know how much the other axle has.

Gary

spdbrake · #8 (**permalink**) 07-23-2019, 07:46 AM

Hauss,

The Newer BDR half-shafts could be Backdraft Proprietary. I kinda doubt it though. They look like Audi A3, VW Jetta front half-shafts. But that's "looks".
If you can take one to a large NAPA warehouse and start opening boxes you could possibly find a match.
The Iconic pricing is not too steep honestly for a quality axle though. OEM BMW and Audi factory axles are approx $100-200 more.
Also Iconic (Backdraft) stocks items in a niche market and are not BIG box parts stores like Jegs, Summit, etc... I'd expect them to make some sort of profit on these slow moving items.

You may try The Driveshaft shop also. Their stuff is quality Hi-HP rated. Although Backdraft is not listed on the site they do custom axles as well.
https://www.driveshaftshop.com/kit-car-misc-parts

hauss · #9 (**permalink**) 07-23-2019, 10:40 AM

Your right the Iconic parts are reasonable, it was the 1000 hp rated ones, that were ridiculously expensive .

hauss · #10 (**permalink**) 07-23-2019, 08:55 PM

I was wanting someone to tell me if it was the axle or the part that the axle connects to . not sure what the name of all the parts are that connect the wheel side to the axle. the hub?

eschaider · #11 (**permalink**) 07-24-2019, 09:00 AM

Quote:

Originally Posted by hauss

I was wanting someone to tell me if it was the axle or the part that the axle connects to . not sure what the name of all the parts are that connect the wheel side to the axle. the hub?

You are going to have to disassemble the rear end to repair it. Why not disassemble it right now to find out what is broken instead of guessing?

Ed

spdbrake · #12 (**permalink**) 07-24-2019, 09:33 AM

Hauss,

From what you described the backlash for the Axle is probably fine.

If you are seeing a 0.75" backlash at the OD of your 26" tire.
You can shrink that ratio of 13" Radius : 0.75" play by 6 are to come up with a .125" backlash at the (rough centerline is @ 2" radius on the CV joint balls).
https://www.calculator.net/ratio-cal...pe=2&x=91&y=18

Divide that by 2 (2 CV joints on the axle shaft) make its the slop at the Inboard or Outboard CV only 0.625" or 1/16". That gives each bearing only .03125 (1/32") on each side on the Ball for play.

You will probably come up with a lower backlash if you jack the wheels at the hub. Putting the axle at a normal ride (level) position.

hauss · #13 (**permalink**) 07-24-2019, 09:54 AM

Will do, the car drives fine just do not want to have a big surprize. I believe something is wrong . Like I said before everything is tight, just can not figure out why so much play and what would be a acceptable amount.Also the passenger side has very little play.

spdbrake · #14 (**permalink**) 07-24-2019, 10:12 AM

Hauss,

What differential do you have? Open or LSD. On the aft Diff cover there should be a metal tag. an "S" means Limited slip, followed by the gear ratio.
https://lh5.googleusercontent.com/-P..._172840498.jpg

Just curious.

hauss · #15 (**permalink**) 07-24-2019, 10:47 AM

I just set the car on the ground and the play went away checked both sides and they are even . not sure why when unloaded the play increases so much but I guess that is normal I will check the diff and get back to you on the ratio and if is a limited slip. thank you for helping me with this .

hauss · #16 (**permalink**) 07-24-2019, 11:07 AM

Just took a look and no tag . Rear cover has been replaced due to broken axle from another owner. It does have electrical wires that plug into it, not sure what they are for. locking diff, two speed diff, low oil warning ?

spdbrake · #17 (**permalink**) 07-24-2019, 12:15 PM

The plug is for the speedo. There is a multi tooth ring inside the Diff that the Mag pickup counts teeth. Pretty nice as you can change gear ratios and the speedo stays the same.

eschaider · #18 (**permalink**) 07-24-2019, 03:52 PM

Quote:

Originally Posted by hauss

... the passenger side has very little play.

Could be a message here ...

Ed

hauss · #19 (**permalink**) 07-24-2019, 11:01 PM

I too am concerned I will continue to keep an eye on things right now everything is tight and the car drives normal.The play showed up with one tire on the ground and the other jacked up so I could get under the car to check on things. I do have the new style half shafts and was told by backdraft they are rated for 550 hp.

hauss · #20 (**permalink**) 07-27-2019, 01:00 PM

Ok. found no issues with hubs or axles.both driver and passenger wheel with rotate the same 3/4" aprx when other tire is on the ground guess this is normal.Thank you spdbrake for your inputs, they helped put me in the right direction.