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Suspension and Brakes

Posted: Sat, 29 Jan 2011, 5:26 pm
by DanBoy
I have finally got round to starting work on the Porty today. The suspension units are quite rusty, the backplates on the brakes have fallen apart and the brake linkage is broken. I have bought new M8 threaded rods and clevis's (should that be clevi) so the linkage is not a problem but I happen to have two new suspension units in the shed which will take mini hubs and drums. They are 500kg so within the weights of the unit. Despite having just bought new bearings and shocks I am tempted to fit the new units and find some mini parts to finish. Does anybody have any thoughts as to why this might not be a good idea? :? By the way, the bearings in the old units seem quite sound with no play and plenty of grease. I am hoping to use the old brackets to fit the Triumph Herald shock absorbers but will need to make a bracket on the new suspension unit if I go ahead.

Re: Suspension and Brakes

Posted: Sun, 30 Jan 2011, 7:31 am
by txfsealord
Hi Dan,

If you're using any of the original clevises, the thread in them is 5/16"UNF, not M8. When assembling the brake-gear, you can't use lock-nuts on the inboard ends of the cross-rods as the rotation of the suspension trailing arms has to be resolved by the rods turning slightly in their clevis-threads. When people forget about this, wear on the clevis-pins is very rapid.

If you do change to your Indespension units, please may I buy your old torsion-bar axle? In my opinion, they are a much nicer unit than Indespension!

Steve Lord

Re: Suspension and Brakes

Posted: Sun, 30 Jan 2011, 11:26 am
by DanBoy
How did I know that you would be the first to reply? :thumbup: Thanks for the advice. I have bought new clevis pins with an M8 thread plus a new turnbuckle. My porty doesn't have the torsion bar axle (it's a 68) but utilises the individual suspension units. I will heed your advice about not fitting locknuts.

Re: Suspension and Brakes

Posted: Sun, 30 Jan 2011, 8:42 pm
by DanBoy
The suspension unit is now removed. I thought it would be easier to assess it in the relative comfort of the garage. Now I find that the Herald shock absorbers I bought are different in that they have a round eye fitting at the top instead of a bolt, so it looks like the towsure units are going on without shockers. As for the chassis, I have already made up some repair plates for the front and will be doing the same with the suspension mounting points. Looks like the mig welder is certainly going to earn it's keep over the next few months. :lol:

Re: Suspension and Brakes

Posted: Sun, 06 Feb 2011, 7:49 pm
by DanBoy
Well, having bought some mini hubs and drums etc, and started to rebuild them I have now found that they are going to cause more problems than they will solve. The handbrake pulls forward and there is nowhere to mount a quadrant unless I weld a complete chassis member on. The brake rings on the suspension units just wont allow the back plates to bolt on either. I have now abandoned the mini set up (anyone want to buy suspension units, hubs, drums with spacers and all brake fittings? No, thought not :sick: ) I am now cleaning up the old original units and I think that I will be able to rescue them. I have welded on a clevis pin to take a M8 rod to the original brake mechanism and I have cleaned up the back plates which weren't as bad as I had originally thought. A coat of paint and they should all look respectable again. I will post up some pics when I have got the one side back on again. Oh, and I've ordered some mini shock absorbers which I hope will fit.

Re: Suspension and Brakes

Posted: Mon, 07 Feb 2011, 7:35 pm
by txfsealord
To convert a forward-pulling brake expander to an inward pull, simply weld a rearward-facing arm to the end of the link which protrudes from the backplate, or cut a new L-shaped link from 1/4" solid sheet. A suitable length is usually about 2" (from the side of the existing link to the hole centre on the new piece). Heralds, which I believe you mentioned somewhere, have exactly this shaped link in their wheel cylinders, for this purpose.

To enlarge the bore of the backplate, a lathe is required. Set the plate in an independent chuck (or bolt it to a faceplate, in a small machine) & clock the existing bore before turning. Relying on the outer diameter of the plate for concentricity is not sufficient. If the new backplates' bores are too large, cut the middle from the old ones & weld to the inside face of the new parts. Be careful to get 'em concentric, odd-leg calipers are a help here but it can be done by ordinary measurement.

Steve Lord

Re: Suspension and Brakes

Posted: Tue, 08 Feb 2011, 1:59 pm
by DanBoy
You are right Steve (as usual) :thumbup: I hadn't thought about converting the pull. The back plates didn't have a problem with the bore, it was the suspension arm that was in the way of the original holes. I have solved that problem by redrilling the holes in the back plate so it looks like I am going the mini drums route after all. The benefit of this is that I should be able to fit 12" wheels but I will have to wait until it's all fitted on to check the clearance first.

Re: Suspension and Brakes

Posted: Thu, 10 Feb 2011, 3:27 pm
by DanBoy
Another day of fixing...... The drums and brakes are now fitted to the suspension units and the back plates have been turned slightly so the pull is now upwards. This should allow a cable to feed through a pulley and on to the compensator. I may have caused a big headache in the brakes pulling on as the suspension moves but we'll see...

Bear in mind that I am working on one side at a time so I will have to do all of this again for the other side. :crazy:

Re: Suspension and Brakes

Posted: Tue, 15 Mar 2011, 3:59 pm
by DanBoy
Well I've finally got round to fitting the suspension on both sides. I am now running on mini hubs although I still need to connect the brake linkage up.

Here it is fitted:
suspension012.jpg
I will be borrowing a 12" wheel to try for size and if it fits OK my local mini man will sell me three with good tyres. There are still a couple of bits to do like drill another hole in the Indespension unit to match the original mounting as the corner sits right under the chassis brace. I have also now had the opportunity to take the roof off for repairs but that's another post.