TR6 TR4/TR6 Steering rack question

[SCguy]

I installed my new steering column pieces only to find that the column was not quite lining up correctly. Come to find out that I have what looks to be a TR6 rack in my early 62 TR4 and that when I tighten up the rack the welded washer next to the rack mount (second pic) prevents the column (ever so slightly) from lining up correctly.

So here are my thoughts. I ordered some solid rack mounts in the hope that they are a little narrower than the rubber mounts which might allow the rack to move by an 1/8" or so. If this doesn't work I will attempt to find the correct rack (Doesn't TRF sell them rebuilt).

So what are your thoughts. Should a TR6 rack work? What holds the rack in place on a TR4 beside the rack mount clamps? On a TR6 the large washer welded to the rack I suppose helps.

 

[4aNot4]

The early TR4 rack that mounts the way yours does is a different length than the later TR4, 4A, 250 & 6 rack, which have a different mount arrangement. I think you may have to source an early TR4 rack, maybe others know for sure.

 

[4aNot4]

OK, I see. They used the later rubber compression mounting on the earlier "Mickey Mouse" rack brackets found on early TR4s. As per my first post, I think that the length of the early TR4 rack is different than the later ones.

 

[SCguy]

Here's a little bit of additional information...

I called The Roadster Factory this morning and asked if I could use a TR6 rack if I could get it to fit. Thier answer was, "Yes" so hopefully the solid rack mounts that I have ordered will allow the rack to shift ever so slightly to the passenger side.

 

[4aNot4]

I looked up the differences in the racks. Around CT20000, the mounting arrangement changed to the later style (rack mounts to horizontal brackets). At the same time, the length of the rack housing was increased, but overall length remains the same. Supposedly the later racks won't fit the earlier TR4s, but sounds like you are going to be creative and so go for it. If it is the "tabs" that are the problem, you could always grind them down. Also, TRF, as good a parts supplier as they are (and I am a satisfied customer), has not always provided accurate tech info to me. That's understandable because there are a lot of nuances with these cars. I hope that they are right in this case.

 

[TR4nut]

Larry-

Is your rack hooked up to the tie rods and vertical links already? That would probably mean it is a late TR4 rack. I believe TR6 racks are the same as later model TR4, but the inner tie rods of the TR4 are different length (longer)than on the TR6. If in fact you have a complete TR6 rack stuck on there now, be careful and make sure the tie rod ends are threaded sufficiently onto the rack. Just a thought.

Randy

 

[Alan_Myers]

Hi Larry,

Who did you talk with at TRF?

Your car definitely should have an early style R&P and already should have solid aluminum mounting clamps. If it's mounted in rubber and from the looks of the rack in the picture, someone has already been quite creative. I'd trade that for an early rack asap. The simply two types of R&P are not interchangeable. The length of the tie-rods, inner ball-joint pivots and other dimensions differ.

The only way to use the later type rack would be to pull the engine, radiator, etc. to get a clear shot at the frame members, cut off the old R&P "rabbit ear" brackets and weld in a set of the newer flat type mountings (late TR4 through TR6) that everyone curses about when it comes time to pretension the rubber R&P mountings (if they haven't already retrofitted the aluminum clamps from the earlier R&P). This would be a high precision job that needs top quality welding and a lot of access to the frame in the engine compartment.

If you instead get hold of an earlier R&P to use with the existing brackets, check while swapping the R&P units that the "rabbit ears" are solidly welded in. They tend to flex and then crack around the base, right where they join the main frame rail.

As early as your car is, there might be two gussets missing, too, that helps secure the brackets. Triumph added them mid-production. The ungusseted type are particularly prone to cracking. If omitted, I'd make a point of welding in a pair of gussets (they tie from the "rabbit ears" over to the brackets on the frame that support the big, horizontal, inner pivot pin for the front suspension arms.

You can see photos about adding these gussets on my web pages, at the link below. This gusset was missing from a code "B6" or "B8" frame (forget which) from a '62 that was replacing the slightly later "C" frame on my car, which had the gussets. (Unfortunately, I don't know the commission # of the car that was the source of the slightly earlier frame.) Otherwise, this frame is identical except for a missing exhaust hanger bracket.

I think it would be tricky, but possible to weld in these gussets and repair any cracks near the base of the "rabbit ear" brackets without removing too much from the engine compartment.

There are additional gussets and reinforcements possible with the early, "rabbit ear" brackets, but most of those mods would pretty much require a stripped engine compartment, possibly even lifting off the body.

How important are the gussets? Well, I can tell you the "rabbit ears" on my original frame - with the gussets - were in good shape and unbroken (frame had a rough life and was damaged elsewhere, but will be getting rehabbed too). The replacemnt, but slightly earlier frame was very clean and all welds were solid... except for those two un-gusseted brackets, which were hanging on by a thread!

If I remember correctly, the factory manual has some dimensions on the frame chart, showing precise locations of the R&P mount. Actually, I made up a jig to hold the brackets in place when I was working on the frame. I'd be happy to lend it to you if you need it.

So, in a nutshell, I recommend you track down the correct R&P, which will need the solid mounts you have already ordered, and check over the mounting brackets carefully before installing it.

 

[SCguy]

OK... I've read all of your replies. Here's where things stand. I ground down the mounting side of the tabs on the TR6 steering rack. By shaving about 1/8" off the aluminum mounting blocks when I get them, the rack should fit perfectly centered and snug with the tab flush to the mounting bracket. So with the rack mounted and centered am I reading that because of the inner workings, the rack still won't work?

Does any one have a line on a good used early TR4 rack? I'd much perfer to just do it right. /ubbthreads/images/graemlins/savewave.gif

 

[4aNot4]

Well, TRF does build these racks. They may take that TR6 rack as a core exchange on an early TR4 one...if the mods you have done are not too severe...otherwise they want @$85 as a core charge. They charge around $279 for a rebuilt rack.

 

[TR4nut]

Larry-

I took a look in my TR4/4a factory manual and will amend my concern on the inner tie rods. For TR4a, the tie rod length is 8.42", for the TR4 (early and late), the length is 8.55". Seems like an awfully small difference to me so I doubt that even if you have a TR6 rack there is a problem with the tie tods.

I remember someone talking about other rack differences such as number of turns lock to lock, but the main physical difference you've already been working on is the mounting tabs. I think you'll be fine with the rack you have, and over time you can always hunt for an original rack to tidy things up.

Just my opinion.
Randy