Replacing Diff Flange Studs with Bolts?

[lateracer]

Getting ready to tow my track car to a race and I don't own a flatbed trailer, so I have to rent one. Real bummer because on this baller's budget, renting a trailer for 4 days is a tough pill to swallow when combined with all the other race expenses. A tow dolly would be preferable b/c they're cheaper and would be easier if the drive shaft wasn't such a pain to disconnect.

It's a manual transmission and I know some people say you can tow them in neutral, but other credible people say you can't...then there's the possibility of blowing a shift fork and having the car get stuck in gear. Let's pretend we're in that situation for this conversation.

Yesterday, I was talking with a friend about how the E-30 drive shaft kinda sucks because it's such a pain in the ass to disconnect (exhaust, shields, CSB, guibo, etc.) where as on other cars you can just unbolt the flange that connects the drive shaft with the diff and be done with it. Not an option on these cars though because the rear flange uses studs.



Has anyone ever done (or considered) replacing the studs with bolts?

Another idea that was tossed around was knocking out the rear U-joint and replacing it with a replaceable/greaseable one and a different flange that was more suited (beefier?) to bolts than studs.

Thoughts? Obvious shit I'm overlooking?

[5KWattson]

throw it in N and tow the bitch never once not ever have i heard of anyone having a problem with towing a manual tranz car in neutral...and my buddy owns a tow shop for the past 5 yrs

[lateracer]

From what some people are saying, you can burn up your output bearings by doing a dolly tow for long distances, which I am (San Diego to Sonoma).

http://www.maxbimmer.com/forums/showthread.php?p=620702

http://forums.bimmerforums.com/forum....php?t=1174153

[5KWattson]

hmmmm fuck that is a bit of a distance...but what makes towing it different from driving? MT dont have fluid pumps, the fluid circulates on its on and if your towing with the rear down the fluid will be more apt to keep it lubed giving a front upward angle

[lateracer]

That's kind of what I was thinking too... I don't really understand transmissions well enough, but from what I read, it sounds like the syncros circulate the oil. I was thinking that between overfilling the oil a little and tilting it up should cover it, but I would definitely kill myself if I drove the car all that way (not to mention all the other work on the car itself) to find it had a cooked trans.

Got another race in Fontana - which is closer - in the coming months that I'm definitely gonna flat tow for. Just not sure for this long distance thing.

[browntown]

I like the idea of switching to bolts, but don't know the risks involved.

[DJB]

Consider using my advice in this thread:

http://forums.bimmerforums.com/forum/showthread.php?t=1174153

Stopping for 2 minutes every half hour to let the engine idle might sound like a PITA, but it will take less time than unbolting. Just think of it as a good break while driving.

[lateracer]

Definitely agree that the two minutes an hour is way better than pulling the driveshaft. I wound up getting a flatbed for this tow, but I'm still going to be towing to other tracks in the future. Tow dolly would still be a first choice.

There are a few driveshaft shops that work with BMWs around me. I'm eventually going to get two differentials rebuilt (E30s with good bearings in the diff just aren't around anymore) and might see what their thoughts on a stud to bolt swap are.

[twistednut]

I used allen head bolts on the kids car when his new drive shaft came without the studs. I had to partially grind the head to make it fit but it worked. I don't think your idea will work because the drive shaft has a cup in the end that fits into a recess on the diff input shaft. Thus you would have to loosen the collar nut on the drive shaft each time you wanted to unhook it.