144 steering column

jrhendo

I have 2 active 140s: my 1974 rally car and a 1973 142. On both of them the steering column tends to move downwards with the obvious risk of trying to disengage the safety slip joint. I’ve heard of it happening on other cars.

My observation is that the column is restrained at the top end by plastic slides that are designed to slip on impact and nearer the firewall by a rubber lined U-clamp.

Is the foreword movement of the column inevitable over time or is there something else that should be restraining it?

Roinik

It happens on all 140s. I'd be replacing the 50 yo rubber at the firewall, removing the shear bolts at the top and replacing those wih some Grade 8 bolts. Just check the thread first, as one is likely to be metric and the other UNC.

jrhendo

So it’s a bad design. I have replaced the shear bolts. The problem is that once it’s slid forward, the bolts are hidden by metal and the only way to make it safe again is brute force on a long lever off the manifold!

Roinik

Yeah, it's what should have been called a prototype.

jrhendo

I’m planning on using a 244 column in the 144 rally car. A cut down (shorten the splined parts) 240 secondary column will join the steering box and main shaft with 3/4” x 48 spline uni joints. I need to wait until the 144 gets home but I measured off my 1973 142 and it looks like it’ll just fit. I’m also going to weld a tab on the outer steering column inside the car that pushes on the lower steering column u-bracket. That should stop the whole thing moving forward/down and stressing the steering box.

Spac

It has been a long time since I needed to think about this issue, but I do remember considering about two options:

Replacing the “drive pins” in the collapsible part of the column with bolts, including a washer to limit the amount the column can collapse in a non-crash situation.
Memory is hazy, but maybe aluminium washers on the end to retain the ability to collapse in a crash.
Small R-clips in the original pins, which will shear off in a crash, but will limit the forward/downward movement of the upper column the rest of the time.

I suspect that your 240 column conversion is probably a better option.

jrhendo

Spac on P2P this year, I used solution 1. with a couple of 3/8” drive sockets to space out the rubber bushes.

A previous owner of the car, must have thought of 2. because I found a small hole drilled in the top of each pin when I removed them for 1. above.

I suspect welding a tab on the outer column, or even an exhaust clamp around it adjacent to the retaining U-clamp would solve the problem. I’ll do that but continue with the 240 option because the inner bearings on the 144 column are shot.