Cleanin' Ma Nuts... with the wifes toothbrush

Welcome to another episode of A.R. Mechanic... tonight we are going to clean the inside of our lug nuts, because we just drilled them for safety wire and, when knocking out all the steel shavings, looked inside and noticed how filthy dirty grungy our nuts were.

Step 1:  Find your wife's toothbrush; it's been used once so it's ready for the trash bin - might as well reuse it.

Step 2: Spell check Step 1, and check grammar and font serifs for misplaced pixels. Nasty, filthy misplaced pixels...

MGB Rebound Straps - The Bad and the Ugly

[UPDATED 2012-04-03; scroll down to view]

 

We replaced the drivers side MGB Rebound Strap (aka Stop Strap) before the first race in 2011 - and here is a pic of it today, almost split through:

  

Yikes.

Could be worse though; below is the passenger side rebound strap that we could not remove due to a rusty bolt. Gnarley! But notice it's still hanging in there, probably due to the OEM high quality strap that has thread / rope embedded in the rubber of the strap. 

An attempt at a close up; it's fuzzy not because it out of focus, it fuzzy because IT'S DAMN FUZZY!

Someone should probably do something about that...


[UPDATE 2012-03-24] Turns out the "new strap" in the first pic is split all the way through in the bottom eyelet. This was the cause of Randy's Clunk described (and then subsequently ignored) in the Charlotte 2011 race report. When we replaced the strap last winter, the old bushing (which goes inside the rubber strap eyelet) was rusted tight to the holding pin / bolt - we could not get it off, so we left it and put the new strap right on it. Which then proceeded to sand through the new strap to weaken it enough to break when the very old and very cheap and very tired tube shocks let the axle fall too fast. Sigh. Updates later, as the tragety unfolds (the rusted pin / bolt is no longer available for sale - must step lightly here with only 3 weeks till next race!)


[UPDATE 2012-03-25] As expected, the passenger side bolt immediately sheared off when I tried to loosen it. %$#%#% oh well. As Forrest Gump sagely said: "That's good; one less thing to worry about."


[UPDATE 2012-03-30]

That split shown up in picture 1? It was all the way through:

3 Races old :-(

Time to order new straps... but how to stop them from splitting again? StrappingLad in the USA makes very nice replacement straps out of webbing that won't split; I emailed a question (my suspensions been lowered, do I need shorter straps?) but time has expired on a response, since I have a race in 2 weeks. 

I also didn't like the zero-stretch attribute of the webbing-based straps. "Step Functions" are a bad thing in most engineering practices, and this sudden jarring stop is probably no different. i wanted a little give first (as the original straps were designed) but then a final solid measurable maximum stopping length (like StrappingLads has).

So I talked my pit crew into sewing up two double straps that are about a half inch longer than the rubber based original-but-new replacement rebound straps:

MG Minions

The final result. Top is the $3 FRAKTA strap from Ikea that we hacked up and sewed (I have NO frakta idea what it was intended to be used for), middle is the strap on it's side, bottom is the strap around one of the rubber rebound straps:

 

 Encased MGB rebound strap installed, drivers side:
 

Encased MGB rebound strap installed, Guinness cooler side; note use of cotter pin and washer to hold lower strap on luckily when the rusted bolt snapped off it left enough threads to drill - since the strap takes no side-to-side force, it's just meant to stop it from slipping off.

 

The lower attach post with broken off thread, cleaned up with dremel and coated liberally with rubber-friendly silicone lube:

 

Note: DO NOT DO WHAT IS PICTURED BELOW:

Bad idea #2352

After a raucous discussion on the email list about rebound straps I somehow retained the misconception that the lower strap eye has a metal bushing just like the upper strap eye (you can see the bushing in the lower left of the FRAKTA pic above). Leading me to the conclusion that is was rusted on the post, and a few on the list agreed with me (they probably thought I was talking about the upper post). Long story short, I tried to dremel off the rusted-bushing-that-never-was and of course cut into the post itself... which is welded to the axle and very hard to replace, if you can even find them for sale.I stopped after about 1/16th of an inch when my dimly lit Lucas light bulb finally flickered on over my head. DUH. Sigh. So... repeat... don't do that.

LINKS:


Some great links, until I clean up this page:

• Really great documentation of the same problem I am fighting: http://www.mgb-stuff.org.uk/axletext.htm#reboundstraps and in-depth bigger pics: http://www.mgb-stuff.org.uk/rr.htm#3
• Non-rubberband straps: if he doesn't answer my email in 2 days I will make my own eh: https://sites.google.com/site/strappingladshop/mgb-axle-straps

Wheels & Rims & The Plans of Mice & Men

Quick note on the rims we're running with. 

I removed the caked on grease & muck from the rims to take to shop to get new tires installed on them.

And while we were installing new tires, I dug out the two nicer rims that we scrounged from Crazy Ray's U-Pick-It, U-Pull-It that were on an old Datsun 260Z (it only had 3 attached); these rims have "cooling holes" in them, I figured I should put them on the front to help cool the brake calipers.

Vented rims on left, rims we were using on the right:

A collection of American Racing 4x4.5 rims

I decided I better measure the heck out of them to make sure they fit properly.

Long story short, both styles are exact matches, but both are +10mm offset instead of MGB spec’s +22mm wheel offset. Oops.

Both clear the calipers & suspension ok, so I think this just means the bearings et al get more leverage on them and will wear sooner.

The big difference between the rims is a show stopper: the lug nut holes on the “vented rims” are flat faced and deeper (20mm), causing the lug to use half the threads that it does on the non-vented rims (which have sunken and beveled holes, with steel inserts). The MGB lug studs are only 25mm long.

The MG lug nuts want beveled seats.

Non vented: blue is flat shoulder sunk 6mm in, white is additional 4mm beveled edge (these have steel inserts but you can't tell from the photo):

 

Vented rims: chalked area is flat face, about 0.5 mm sunk (the dirt makes it look deeper):

Sigh.Oh well. Not brave enough to alter the lug nut hole profile... yet.


Update 2013-05-22:
I was going to order a set of the steel inserts and drill out the Datsun 260Z American Racing 4x4.5 rims (on left of first photo above, with the vent holes)... until I stumbled upon the proper solution: Mag Lug Bolts.

The MGB takes 1/2-20 thread bolts; the trick is to get a set that has a shaft/collar that fits snugly into the wheel rims lug hole, is long enough to get plenty of threads but short enough so it does not 'bottom out' on the top of the lug. After extensive measurements with a caliper and taking one of the rims to the local Advanced Auto Parts store we found the perfect fit, right there on the shelf! Note hard steel washers included. Dorman - Autograde Wheel Nut Chrome Std. Mag 2-Pc 1/2 Inch-20, Hex 13/16 Inch Length 1.664 Inch part number 711-208

I mounted the wheel with only two opposite lugs to test how well the centering of the wheel on the hub worked - and it's quite fine thank you very much! Quite happy now.

DORMAN Chrome Wheel Nuts, 1/2-20 threads for MGB and American Racing mag wheels (flat lug seats)

Mag Lug Nuts on American Racing 4x4.5 mag wheels mounted perfectly on MGB

A few great links:

The MG Experience: MGB Tire Sizes

http://www.mgexperience.net/article/tire-sizes.html

The MG Experience: MGB Wheel Cross Reference
http://www.mgexperience.net/article/wheel-xref.html

MGB Stuff.org 
http://www.mgb-stuff.org.uk/offset.htm#2
http://www.mgb-stuff.org.uk/wheelstext.htm

Steel Inserts for Aluminum Rim Lug Nut Holes 
http://www.prestigewheel.com/RetaiWheelInserts.asp