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Technical Area => Suspension Related Items => Topic started by: march2013 on February 15, 2013, 11:20:24 AM

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Title: Wire Wheel Conversion
Post by: march2013 on February 15, 2013, 11:20:24 AM
 I have a '70 MGB roadster that I'm changing from wire to disc wheels.   And I know it's not as simple as it sounds.  The cotter pin inside the front wheel hub(s)
has proven to be a bugger to remove.   Please convey any and all suggestions.  I'm not concerned about replacing it although it would be interesting to know how the factory installed them initially.

Bob Crane
Title: Re: Wire Wheel Conversion
Post by: Art on February 15, 2013, 11:24:52 AM
Those pins are no fun even when they are cooperative.
My suggestions to you are as follows:
First, clean as much gunk and grease away as possible.
Get a long, narrow drift, chisel or flat steel piece that can fit down inside the splined hub between the hub and spindle, into the slots of the castellated nut and is long enough to be tapped with a hammer from outside.
Also, you will need a narrow pin or drift to push the cotter pin out, a set of long needle-nosed pliers that can fit into the hole in the spindle to grab the pin, a narrow bent rod or hook that can be used to pull the cotter pin out by it's eye and a pair of vice grip pliers.
Make sure the car is VERY securely supported with the front wheels off.
Align the holes in the splined hub with the cotter pin and use the needle nosed pliers to turn the pin such that the turned tab ends are parallel to the spindle.
Use the long drift to try to straighten the bent ends.  Turn the cotter pin 180 degrees and repeat and turn 90 degrees so that the eye of the pin is visible on the opposite side.
From the other end of the pin, put the bent pin in from the hole in the hub and force the bent end into the eye of the cotter pin.  This may require using an awl or other pointy tool to open the end of the cotter pin eye enough.
Grab the bent pin shaft with a vice grip and try to pull the cotter pin out.  This may also require gentle persuasion with a hammer to move or, if the bent ends of the cotter cannot be straightened enough to fit through the hole on the spindle,cutting those ends off with a cutter or sharp chisel first.

If it moves enough to get into the spindle, but proves too tight for the bent pin to remove, you can then use to drift pin and hammer from the other side to force it out.
Similarly, if you can only get the pin so far out, it might be easier to cut off the "eye" and push the pin the other way out.
In total frustration, I've removed both ends of the cotter pin as close to the castellated nut as possible and used a deep-well socket and a long breaker bar with a pipe on it to just remove the nut and shear the pin off.  This is a last resort as it can do significant damage to the threads on the spindle and/or nut
That's about the best advice I can give you.
One more point on the rear axle:  If this is a legitimate factory wire wheel car, the axle will be considerably narrower that a disc wheel car.  About 1.5" narrower.  Just changing the hubs at the ends of the axle could have the tires rubbing the bodywork on the inside.  
If you do not want to change the axle for full-width disc wheel one, use either off-set wheels or a spacer or adapter kit with the disc hubs to position the tires correctly.  The adapter would be about 3/4" thick, bolt to the hub as the wheel would, but have another set of studs between the holes to the axles studs for the wheels.  The thickness would increase the axle width enough to have the disc wheels in stock position.  Similar for a spacer, but you may need longer studs in the disc hubs to accommodate the added width.
Off-set wheels would move the back-plate of the wheel to the back (3/4" in this case) so as to compensate for the narrower axle.
For the front, changing the hubs is all that is required to use stock wheels.
I hope that helps you.  Let me know how you make out.
Art Isaacs

Title: Re: Wire Wheel Conversion
Post by: march2013 on February 16, 2013, 11:38:37 AM
First of all, thanks so much for your prompt and thorough reply to my email of Feb. 9.   Dumb me!!  I now see that the hole in the side of the hub aligns with the cotter pin and by rotating the hub 180 degrees so that I can get at each end of the pin, I should be able to loosen & eventually remove it!!   I can't turn this pin, as you suggested, because the legs of the pin are flats that just fit the slots of the castellated nut.  When it gets warmer in my garage (I live in Northwestern IL), I'll start working on it again.

I do have the hubs for the front disc wheels. And for the rear, I was able to locate a disc wheel type rear end assembly. I have steel disc wheels (relatively cheep) that are 15 x 5.5" that I think are from a Triumph TR6.   Comments ??

Thanks Again,
Bob Crane

Title: Re: Wire Wheel Conversion
Post by: Art on February 16, 2013, 11:40:07 AM
Hi Bob,
Very good.  The rear axle swap is fairly easy and straight forward.  I did a write-up for the Tech Section some time ago (albeit the reverse-disc to wire conversion, but it is much the same).
I don't know that TR wheels have the same bolt pattern as the B, but could be.  More likely is that the 15X5.5 wheels are from an MGC, as that was their stock size and they used exactly the same hubs and axles.  
On these wheels, I'd go with a 185R60-15 tire.  It's called a "Plus 1".  The different aspect ratio/lower profile (60 vs. 70) tire keeps the overall diameter the same as the 14" wheels (about 24") and the footprint pretty much at maximum.  
One more point on the rear axle - you will need to replace the handbrake cable.  The one for the wire wheel axle is shorter and will not fit.  It will also likely deteriorate in removal.  Not worth the effort to salvage.
Good luck and keep in touch.  Can't wait to see the finished product.
Safety Fast!

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