Rear suspension lowering blocks

[Adrian Saunders]

So, the rear suspension lowering blocks don’t come with a dowel to locate to the diff casing but the stud clearance holes are accurate and close clearance. Engineering-wise not correct but in reality, probably ok. However, I’m inclined to dowel the block to the diff to get everything as good as possible. Anyone else done this? 

[Pete Lewis]

i fitted a 1" on the vit6 but i cant remember  .used when dumping the swinger for a courier  i do remember adding the extra 2 stud holes and got  the offset  back to front 

so loads of holes  Ha!!  you could fit it anyway up 

they do locate in the machined spring bed on the diff hsg. quite  tightly..

Pete

[dave.vitesse]

Pete, The original design had a spring around the same loading as the Courier version. The Sales people said it was to hard and so the production cars had a much softer spring.

Dave

[johny]

My block came machined with a stepped underside so it fitted tightly into the slot on the top of the diff. This leaves only the possible side to side movement on the stud holes but if clamped properly won't move...

[johny]

My block came machined with a stepped underside so it fitted tightly into the slot on the top of the diff. This leaves only the possible side to side movement on the stud holes but if clamped properly won't move...

[johny]

My block came machined with a stepped underside so it fitted tightly into the slot on the top of the diff. This leaves only the possible side to side movement on the stud holes but if clamped properly won't move...

[Pete Lewis]

Ha Jonny you have 3 blocks   ????

Pete

[johny]

I wish I had 3 Triumphs to fit them to😥 but no it was down to a severe case of impatience...

[Mjit]

I've got a lowering block (started with 1" but decided it was too much and happy now on 3/4") and having had the spring/block in and out a few times for one reason or another I'd say you're just making trouble for yourself if you dowel the block to the diff.  It's hard enough jiggling everything in and out as it is, would be a bloody nightmare if both the block and spring were dowelled!

[p7rider]

I made my block with a 3/4" hole in the middle where the dowel should go. Then I turned a stepped pin to go in it . So 2 diameters one 3/4" the second 1/2" this allows the pin to locate the block in to the diff. Next the 3/4" diameter I bored out to 1/2" to take the dowel fitted to the spring. So everything lines up perfectly. A picture would help if I had one.

[68vitesse]

In the middle of removing the differential from my Mk1 Vitesse on reassemble thinking of using bolts instead of nuts and studs to fix the spring to the diff.

Can't think of any reason why not as long as I'm careful about the length, unless others know different.

Regards

Paul.

[PeteH]

6 minutes ago, 68vitesse said:

In the middle of removing the differential from my Mk1 Vitesse on reassemble thinking of using bolts instead of nuts and studs to fix the spring to the diff.

Can't think of any reason why not as long as I'm careful about the length, unless others know different.

Regards

Paul.

I`m thinking a little Pedantry here, so bear with me. As I see it the studs bottom out in the Casing? (I think) and as such have the maximum thread length and by definition the full ("tensile") strength of the threads. If however you fail to get a full depth, the strength of the bolt will be compromised?. And if they bottom out before they exert the full tension on the Spring you could have a "loose/slack" spring but the correct torque reading?. To acheive the desired end will need very very carefull management.

Pete

[JohnD]

They go right through into the hollow of the casing.

The pool of oil from an emptying diff that was laid on its side proves it

[johny]

Yes and then the studs are threaded so that they cant go in too far.

Cant see any problem with bolts as long as they are the right length but of course dont know if they will then be long enough to engage and pull the spring down into place. If they do then youre pulling the spring down without having full thread strength in the casing...

[Pete Lewis]

1 hour ago, 68vitesse said:

thinking of using bolts instead of nuts and studs

Ok why would you want to do this idea ???

agree you can easily run into disaster   and for what ???

Pete

[Colin Lindsay]

1 hour ago, PeteH said:

I`m thinking a little Pedantry here, so bear with me. As I see it the studs bottom out in the Casing? (I think) and as such have the maximum thread length and by definition the full ("tensile") strength of the threads. If however you fail to get a full depth, the strength of the bolt will be compromised?. And if they bottom out before they exert the full tension on the Spring you could have a "loose/slack" spring but the correct torque reading?. To acheive the desired end will need very very carefull management.

Pete

On my Herald restoration thread I fitted a refurbished rear spring, and it was almost six inches above the diff casing when attached to both links. I was very wary of the strength involved, there's a lot of tension, so ended up attaching only one end of the spring to one of the vertical links, letting the other end drop down (tight to the axle). Only by doing this was I able to get the nuts started on the studs, and tightened it down until I was happy that they would hold with clear threads visible. It then became a matter of lifting the spring, and manoeuvering the end of the other link, until I could get the bolt through. Once I had both in I was able to fully tighten the nuts, almost like torquing a head, tightening in sequence and keeping the pressure even. The studs tighten in the casing until they reach the end of the threads; the top end then screws down, with thread to spare, until the spring is tight.

If using bolts you'd need to very carefully calculate the length, where the end screws down into the diff with no unthreaded part to limit the travel, and I think if they're the length they need to be when tightened they won't be long enough to pull the top plate down initially.

[68vitesse]

1 hour ago, johny said:

Yes and then the studs are threaded so that they cant go in too far.

Cant see any problem with bolts as long as they are the right length but of course dont know if they will then be long enough to engage and pull the spring down into place. If they do then youre pulling the spring down without having full thread strength in the casing...

The spring should not need pulling into place, I've always fixed it to the differential first then lifted the ends to get the verticle link bolt in.

1 hour ago, Pete Lewis said:

Ok why would you want to do this idea ???

agree you can easily run into disaster   and for what ???

Pete

The studs have to be removed to get the spring out so just easier.

Many things can lead to disaster if you get it wrong, but not a reason to not try it important word is if.

Regards

Paul

[PeteH]

11 hours ago, Colin Lindsay said:

To acheive the desired end will need very very carefull management.

I think, (not always the best idea) as I said you will have to be careful, Assumng as john said, their is no limitation at the bottom of the tapped holes, then torqueing up correctly should be no issue. Having the right length of thread in said holes to take the Strain would be the limiting factor. And the choice of Bolt material.

Pete

[JohnD]

If you need to use the studs/bolts to pull the spring into position, the studs won't be long enough, and bolts too long.

Find some threaded rod, fit suitable lengths, not screwed in too far, tighten the nuts down o to position the spring, fit more bolts (if you must) and replace the rods.

[Colin Lindsay]

1 hour ago, PeteH said:

I think, (not always the best idea) as I said you will have to be careful, Assumng as john said, their is no limitation at the bottom of the tapped holes, then torqueing up correctly should be no issue. Having the right length of thread in said holes to take the Strain would be the limiting factor. And the choice of Bolt material.

Pete

From Paul's post above (68vitesse) it will all depend on how much the spring requires to be pulled down. My estate went into place first time and needed less than an inch of lifting for the rear links; the convertible with eleven leaves required a lot of work to get it pulled down to the diff - see photo. There's no limitation in the stud holes, as John says, so that means any excess bolt length will continue on down into the interior; will it go as far as any moving part? That's the calculation you need to be careful with.

Edit: John has just replied above, the method of using longer threaded rod to pull the spring down is the tried and tested method, and that's the way to do it - pull the spring down, fit the studs once you're able, and continue the tightening that way. Even standing on my spring wouldn't compress it down far enough...

[Anglefire]

What is wrong with a stud? With the correct threaded length one end for the diff? Just seems to me that Triumph are not completely stupid with their engineering and did get most things right - this in my opinion being one of them.

Edited April 2, 2021 by Anglefire
Added the word Not!

[68vitesse]

Once my differential is out I will be splitting it to replace the main gasket and will drill and fit a drain plug. I will then be able to see exactly the length of bolt needed so no more messing around with two jam nuts to install or remove the studs.

Bolt length would be thickness of spring plus top plate and any lowering block and length of thread on stud minus spring recess in diff. You could always add any thickness of washer, a bolt can always be cut to length as long as the threaded section is long enough, I would not cut a longer thread on a bolt as a cut thread is weaker than a rolled one.

Regards

Paul

[JohnD]

The double nutting technique works, but puts enormous stress on the threads, just where you want them to grip.     I wouldn't re-use a stud extracted that way.

A proper stud extractor tool is like a long socket, and works by internal cams that grip the length of the stud, away from the theads.   

The picture shows a very good Beta tool, that has a hex head on it so that even studs longer than the tool, like diff studs, can be extracted, as a spanner can be used where a ratchet cannot.

Metric sets are easier to find, and because of their mechanism can work fine on Imperial studs, but get Imperial if you can.

They aren't very expensive, starting at about £20 for a four set.

John

 

[johny]

Once the diff is open you can look to see how close anything is on the inside to the stud holes👍 Also will you do the front seal while the units out? 

[JohnD]

There is no point in inserting the studs/bolts any furher than the thickness of the casing.    No projection at all is needed.

So once you have the studs out, a simple depth gauge will tell you.   A cheap plastic vernier guage costing about £2 will be pefecly sufficient for this job.

https://www.ebay.co.uk/itm/Mini-0-80mm-Plastic-Ruler-Sliding-Vernier-Caliper-Gauge-Measure-Tools-G3R5/274633548438?hash=item3ff16f6296:g:9jkAAOSwO~lftYCG

A metal one wil cost less than a fiver!