Trailing arm reinforcement.

[Carledo]

Another posibility is that you fabricate your own. It's not that a difficult part to make in the shed. The GP2 Dolomites had tr7 shaped arms. Similar as Dolomite but without the angle at the rear so impossible to fold up.

Jeroen

I'm trying to visualise how this could be done, maybe with a view to making a pair or two myself. I can see a straight tubular arm with a ring at either end to accept the bushes, and I can imagine a sort of U shaped saddle welded to the tube, wrapping around the bottom to support the lower shock mount. Query:- Will the very act of welding this saddle to near the centre of the tubular arm weaken the tube itself? How thick would the tube need to be?

All well and good, but this arrangement will effectively lengthen the shocker by a couple of inches at least. So is the answer simply to fit ASP shox and shorter springs and experiment with ride height until it's right?

Steve

[SprintV8]

Another posibility is that you fabricate your own. It's not that a difficult part to make in the shed. The GP2 Dolomites had tr7 shaped arms. Similar as Dolomite but without the angle at the rear so impossible to fold up.

Jeroen

I'm trying to visualise how this could be done, maybe with a view to making a pair or two myself. I can see a straight tubular arm with a ring at either end to accept the bushes, and I can imagine a sort of U shaped saddle welded to the tube, wrapping around the bottom to support the lower shock mount. Query:- Will the very act of welding this saddle to near the centre of the tubular arm weaken the tube itself? How thick would the tube need to be?

All well and good, but this arrangement will effectively lengthen the shocker by a couple of inches at least. So is the answer simply to fit ASP shox and shorter springs and experiment with ride height until it's right?

Steve

Another route is a u section channel steel similar to the original setup.
But thicker then round tubes could be welded to either end to accept standard bush’s or after market type.
The shock would then still be in the original position in the U channel.

I’ll try and do a drawing later on.

[GlenM]

I don't think I have ever come across voided suspension bushes (i.e. suspension bushes with air-holes). Why would one use such things; possibly to increase the effective softness or compliance!?!

They were used on lots of cars, particularly from the 1960s and 1970s. Not air holes as such but more a pair of cut outs in the perimeter of the bush.

[SprintV8]

Void bush’s as they where called.
Where the standard bush’s on the rear axle set up on the Cortina Mks 3/4/5.
But where changed to a solid bush as they lasted much longer.

[sprint95m]

Void bush’s as they where called.
Where the standard bush’s on the rear axle set up on the Cortina Mks 3/4/5.
But where changed to a solid bush as they lasted much longer.

Back in the day, they void bushes were cheaper than the solid versions for Dolomites….

I knew someone who fitted a full set of Ford bushes to his mark 4 every late summer,
that was after knackering the previous set on the annual family caravanning holiday!

There are lots of examples of cost cutting, and fitting void bushes is simply one.




Ian

[Carledo]

Voided bushes (the bane of Cortina III, IV and V owners) are there to improve compliance and ride comfort. A great many modern cars have still got some voided bushes fitted in strategic spots, some wear out quickly and need frequent replacement, others aren't so bad. But there IS a reason other than selling more bushes!

Steve

[naskeet]

Voided bushes (the bane of Cortina III, IV and V owners) are there to improve compliance and ride comfort. A great many modern cars have still got some voided bushes fitted in strategic spots, some wear out quickly and need frequent replacement, others aren't so bad. But there IS a reason other than selling more bushes!

Steve

One of my local friends, whose degree in mechanical engineering during the mid-to-late-1960s, was sponsored by the Ford Motor Company, investigated the effect of varying the softness of Cortina rear-suspension bushes as his final-year project. He came to the conclusion that it was a poorly designed suspension, which was redesigned for the Lotus Cortina, but was not adopted for the later models of Ford Cortina!!! He worked in various Essex based sections of the Ford Motor Company, until he retired about 15 years ago.

[sprint95m]

He came to the conclusion that it was a poorly designed suspension, which was redesigned for the Lotus Cortina, but was not adopted for the later models of Ford Cortina!!!

Colin Chapman redesigned the mark one Cortina to a coil spring back suspension,
however it was only used on the first 1000 Lotus Cortinas (to qualify for homologation),
subsequent Lotus Cortinas were equipped with ye olde leaf springs



Ian

[SprintV8]

He came to the conclusion that it was a poorly designed suspension, which was redesigned for the Lotus Cortina, but was not adopted for the later models of Ford Cortina!!!

Colin Chapman redesigned the mark one Cortina to a coil spring back suspension,
however it was only used on the first 1000 Lotus Cortinas (to qualify for homologation),
subsequent Lotus Cortinas were equipped with ye olde leaf springs



Ian

Au
The rear suspension has been modified to replace the leaf springs with coil-over shock absorbers. The back axle is essentially a standard Ford Banjo axle with modifications to accept the link control system that replaces the springs. This consists of a wide ‘A’ Frame bracket, adapted from the Lotus Seven design, with the single point at the axle and arms attached to the body on the inside of the chassis rails in front of the axle, together with two further anti-tramp bars set on the outside of the chassis rails. . The rear suspension is lower than the standard car, and an aluminium differential nose housing is used to reduce un-sprung weight.
Built Type II – Aeroflow with ‘A’ Frame Available October 1964 – October 1965


I’m sure the guy that brought and resold me back my Sprint had one of these Coil sprung Mk1 Lotus.

[Carledo]

The rear suspension has been modified to replace the leaf springs with coil-over shock absorbers. The back axle is essentially a standard Ford Banjo axle with modifications to accept the link control system that replaces the springs. This consists of a wide ‘A’ Frame bracket, adapted from the Lotus Seven design, with the single point at the axle and arms attached to the body on the inside of the chassis rails in front of the axle, together with two further anti-tramp bars set on the outside of the chassis rails. . The rear suspension is lower than the standard car, and an aluminium differential nose housing is used to reduce un-sprung weight.

Visualise this and you end up with almost exactly a Dolomite rear suspension save the upper arms meet in the middle rather than being a foot apart as on the Triumph.

In keeping with Colin Chapman's design philosophy of "to go faster, add lightness!" the aluminium diff case and A frame were built as sparingly as possible and, as a result, were subject to frequent cracking failures. An older friend of mine ran an A frame LC in the early seventies, a bit of a monster for a road car with an ex works, stage III motor in it that developed over 150bhp, did 0-60 in 6.4 secs and topped out at 145 mph. Nothing locally could even get near it's performance, including the local Plod. He got through at least 1 A frame per year for many years. In those days you could buy them from Lotus. Nowadays they are worth their weight in gold!

The above is the MAIN reason why Ford reverted to cart springs for later production cars. The warranty claims on diff cases and A frames were costing Ford a fortune!

The problems WE have with overpowered Dolomites are picayune in comparison!

Steve

[SprintV8]

They also built a hump in the boot floor to allow the diff to come further up on the later coil sprung cars.

It was possibly cost they reverted back to leaf springs after the homologation cars where built.

[xvivalve]

Standard non-voided bush:



Voided bush:

[GlenM]

Alun,

That's exactly how I remember the voided bushes. They had to be fitted a certain way round too.