CB Cross member help

BOOTLEG · September 17, 2014, 06:16:38 AM

I too must lower my 78 B. Currently ~17" wheel center to chrome. Got a donor CB Xmember and cut the steering rack brackets off and bolted them to a steering rack. Installed and leveled the Xmember and car on jacks laterally. Positioned the rack w/steering rod through the motor mount and in the U-joint. Squared them using the distance from the center tube on the steering rack to the front edge of the Xmember. Made paper templates and cut 3" wide 1/8" thick flat steel into 4 bracket connectors and welded the rack mount brackets to the Xmember in the "new" position. Had fun making it and the steering rotates nicely but not sure I want it on my car because the brackets are not centered.
Comments please.
CB Xmember.jpg

BlownMGB-V8 · September 17, 2014, 06:45:47 AM

Gary, have you considered bump steer? As you move the rack forward the steering arms should normally be lengthened by an equal amount. That's not practical for most so the rack pinion is usually shortened instead. If you have done that please disregard the above.

Jim

ex-tyke · September 17, 2014, 09:42:46 AM

Quote...because the brackets are not centered.

You'll find that if you look at the steering rack alignment on an original RB xmbr, the body is not parallel to the xmbr - the right hand mount bracket is longer than the left, leaving the rack askew - all done to allow correct shaft routing through the engine mount and up to the U-joint.

MGBV8 · September 17, 2014, 10:33:56 AM

Bolt 'er up! Let us know how it worked out. I have one laying in the garage waiting to go under my '79 B.

Moderator · September 17, 2014, 10:38:58 AM

Why didn't you use the chrome bumper crossmember (unmodified), along with a chrome bumper rack?

BlownMGB-V8 · September 18, 2014, 01:00:27 PM

The RB has a deeper firewall cone and shorter u-joint, but still I don't think it works with the CB rack (if he has one). I think you have to lengthen it.

The RB rack has to be shortened 1-7/16", we just did this with the Chump car:
http://forum.britishv8.org/read.php?9,41858,page=3

The CB rack does have a quicker steering ratio though.

Jim

MGBV8 · September 18, 2014, 05:51:24 PM

Mike Moor said he didn't shorten his. I haven't tried it yet. If the rack moves forward, though, it will be into my harmonic balancer.

BlownMGB-V8 · September 19, 2014, 02:25:27 AM

Might want to ask him how he did his, I've see it done a bunch of different ways. It's pretty easy to change the length, especially if you have access to a lathe. But it can be done using a snug fitting piece of tubing and a welder too. Plus it's a good opportunity to assess the condition of the rack and service it.

Jim

ex-tyke · September 19, 2014, 09:00:23 AM

I have another original, unmodified rack in my garage with the CB ratio (2.92:1). I ran it for a couple of years before switching back to my RB rack (3.57:1) - both racks have identical length steering shafts, so no modification required to switch racks.
I can't tell you what year it is from, but clearly the quick ratio rack is available as a direct replacement for the RB rack.

MGBV8 · September 19, 2014, 10:04:35 AM

That's interesting Graham. Wonder if it was just another transition piece?

Jim,

Mike slightly relocated the rack mounts, then it all bolted up. I may have to give it try this winter. Problem is my harmonic balance is only thousandths away from the rack now.

BlownMGB-V8 · September 19, 2014, 11:30:09 AM

Any time you have to mess with the rack mounts, the split coupler/exhaust clamp mount really is the way to go. Simple and easy to make, easy to position, adjustable side to side and in rotation. Makes aligning the rack a snap, just hook it up and clamp it down.

Jim

MGBV8 · September 19, 2014, 03:59:26 PM

Yes, I agree. That was a very slick method on the Roadmaster. In my case, though, the mount has already been modded cause I have Mike's old CB crossmember.

Capt'n Moorgone · September 19, 2014, 08:57:35 PM

Gary,
There are many ways to skin a cat. As Carl said, I didn't shorten the shaft. The easy way is to leave the RB rack hooked to the steering shaft and cut the mounts off the cross member. Leave the rack hang on the car. Remove the cross member. Cut the mounts off the CB cross member leaving about half the bracket in place. Now bolt the CB cross member up. Where ever the rack and brackets land against the CB brackets, weld it together. I'm not sure, but I may have heated the steering arms on the spindle and bent them down to correct bump steer measurement. This set-up worked very well for several years before converting to Fastcars' cross member. I remember Bob Senecar, ASA champ, driving my car and saying how well it handled before I switched to Fastcars' unit. I almost backed out of the purchase. Don't regret the change. Fastcars' unit took #80 off the front end. Take your time, and you'll be happy with the results.