Cortina Based Rear Suspension

[Guest steveyb]

The maximum open shock absorber length should be short enough to retain the spring in its seats. To use a retaining strap is not considered "good practice" even if it works! I'm sure the guys at Gaz would be be able to sort out a suitable pair if you give them the open and closed dimensions. I'm sure if you took a car to SVA/IVA tester thaye would fail a car that used straps to stop the sring falling out!

 

 

Hi Megadodo, thanks for the input, this is what I was thinking, Chris seems to have overcome the spring drop out by effectively increasing spring length which also improves his ride height, I may yet have to do this too.

The car has already been SVAd and has it's log book and a couple of previous MOTs, I bought it off someone who basically just wanted the engine, box, shaft and a few other bits.

As you say, not only would straps be considered 'not good practise', but would I think also be under some fair amount of friction/stress on rebounds and constantly exposed to any road surface throw up. salt, stones, etc.

 

Once I've finished re-bushing the axle, I intend to fit everything back and measure up that critical 'open/closed' shock distance between top shock mounting and axle mounting and perhaps get in touch with Gaz as you suggest if I can't find anything suitable off the shelf.

I was hoping someone may have already solved this and could give an application shock make/ No.

 

By way of interest, below is a pic of the piece on top of the axle that I think may be an axle end mounting of the 'fifth' link already mentioned by Chris, there are holes in the floor that may have held the inboard end mounting:-

 

 

p.s. My last rebuild - a Herald based Spartan was much more straight forward.

[chris n]

I never had a problem with the rear springs falling out, my problem was the car looked like a hot rod but back-to-front

(front higher than the rear) and at the time there was no forum or that much back up from RHE you were on your own so to speak just a build manual that was as much good a paper umbrella in a thunder storm .

So the only way out of the problem was to fit the clamp to lift the car at the rear. Never had any trouble passing an MOT with them fitted too and as there was no SVA/IVA at the time there was no problems

 

Steve the bracket thats fitted to the top of your diff is something someone have made its not a Robin Hood part,

The fifth link set up would have looked like this

 

 

Fifth link set up

 

Fifth link mounting plate bolted to the rear bulkhead

(Sorry about the photos )

 

This topic came up in conversation with a mate of mine today who has a Cortina based Sumo. He had problem with the rear spring coming out as he was driving along in the end he swaped the Cortina shocks for a set of Triumph Spitfire shocks with are shorter in lenght problem solved.

[Guest steveyb]

Hi Chris, ah right, so your reason for the longer springs were purely to 'jack' up the rear.

 

At the moment, I've re-assembled everything (the lower rear bushes - big ones, took some effort to change, even after freezing the bushes and heating the arm) and the ride height on the wheels with driver only is level with 8" front and rear from bottom of frame to floor.

 

Measuring up the set up, with use of jack under diff and original Cortina shocks, it would seem a stroke of 5" and a fully open length of 16" would fit the bill, will have a shufty at the Spitfire shocks, thanks for that.

 

As you say it seems the bracket on the diff is some sort of home made thing, as there's only one hole in it I'm assuming the end of the rod connected must have been just bushed both sides and secured with a nut (tie bar style).

Re your pic, how was the end of the track rod end secured to the diff, was the diff tapped?

 

The present set up of the top in board arm fixing to the body would seem to put a lot of strain on the fixing bolt too as it's only secured to the one supporting side with the bolt and washer, the only answer to that seems to fabricate some extra support on bolt head side, which in turn would require very slightly longer bolts. As the plate is fairly thick, I thought I could maybe 'box' it in as in diagram, or am I being a bit finicky?

 

 

 

Steve

[chris n]

Hi Steve, Got the rear of old Spanky up on ramps today and have been for a crawl about.

 

 

Quick drawing of the rear shock absorber bar (not to scale) as you can see there's not much in it to what your measurements are

Bar length 40" shocks 10" in from the end of the bar and the shocks 20" apart from centre to centre of the bolt holes.

 

 

 

Rear anti-roll bar

 

 

 

Top trailing arm mounting fitted with longer bolts and spaced out with washer with two large washer on the outside to stop the bolt pulling through the void bush.

 

 

 

Top spring mounting plates

Have you found out what springs you have yet? If they are from an estate car you will have to swap them out for a pair from a saloon.

Also when its time to tighten up the trailing arm bolts to there torque settings its best to have the car on it wheels on a flat ground surface.

 

 

 

 

 

Spax Shock absorber

 

 

 

Fifth link plate left in to add strength to the rear bulkhead above the transmisson tunnel.

 

how was the end of the track rod end secured to the diff, was the diff tapped?

 

this is the way they told you to fit the fifth link to the diff casing

 

Drain diff and remove the rear cover. With a 1/8" drill make a pilot hole just off centre on the housing in order to enable fitment of the nut above the gears inside. (bit of a bugger if you drilled into the diff and then couldn't get the nut on )

Then using 10mm drill open up the hole so that the track rod fit into the diff.

(now for the best bit )

To get a tapered fit it will be necessary to WOBBLE the drill bit around so the the taper end of the arm fits nice and fit nut.

 

End result was the nut pulled through the diff casing or the arm just ripped the top of the diff case off the axle.

[Guest steveyb]

Hi Chris, thanks a lot for the time taken to compare your set up to mine.

 

The measurements of the top shock mountings as you say are close enough to make no never mind.

The washers on the inward of the top arms are certainly larger/beefier than mine and certainly look larger than bush diameter, this will be an easier option than boxing in the end, I assume the washers were with the kit.

I see your spring top locator, is also as you say a more snug fit for the spring, I can't see any colour coding on the springs I have to suggest what they are, so will have to see how firm the ride is once on the road.

 

Your reference to the RHE explanation of how the fifth link was meant to be mounted on the axle was indeed slightly hair-raising, more like a 'that'll do' rather than engineering approach.

 

Once I have the rear end sorted, I will indeed only tighten/torque the arms etc once it's on it's wheels and level.

 

Once again many thanks for your help and advice Chris and no doubt I'll back for more.

 

Steve

[chris n]

Hi Steve, thats ok anytime

The washer weren't supplied in the kit, picked them up at a local nut & bolt supplier along with a set of new bolts.

If you need to know the size of the washer let me know and I will measure them up for you.

 

Chris

[Guest steveyb]

Hi Steve, thats ok anytime

The washer weren't supplied in the kit, picked them up at a local nut & bolt supplier along with a set of new bolts.

If you need to know the size of the washer let me know and I will measure them up for you.

 

Chris

 

 

Thanks Chris, they look to be about 1 1/2" inch dia x 1/8" thick and 1/2" bore?

 

Steve

Edited November 12, 2009 by SteveyB