Rear suspension lowering blocks

[68vitesse]

3 minutes ago, JohnD said:

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 only accessible part of the stud, until the spring is out, is the threaded portion.

5 minutes ago, johny said:

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? 

Working on the principle if it ain't broke don't fixit, no.

Regards

Paul.

[68vitesse]

So far so good, diff having a soak while I have lunch.

Regards

Paul.

 

[Mjit]

16 minutes ago, 68vitesse said:

So far so good, diff having a soak while I have lunch.

Regards

Paul.

 

I think this photo might answer the "Why did Triumph use studs, not bolts?" question. If you think about it with the spring and mounting box fitted any fore/aft rock in the spring will get transferred to the mounting box and from there into the top ends of the studs, and down to the diff. casing, which could mean quite a torque being applied to the stud for even a small rock in the spring.

• If they'd used set screws the full length would be threaded, so thinner and weaker.  Potentially the maths may have mean needing to go up from 3/8" to 7/16, which will be heavier/more expensive and might in turn might mean needing more metal in the diff. casting, so even more weight and money.
• They could have used bolts to get around this - but I'm guessing the required "chuffing long shank with a really short thread in comparison" isn't going to be a standard one, so will be a special job and quite expensive.
• But just wanging a thread on each end of a length of steel bar is easy and cheap.

[Pete Lewis]

while the difffs out check the front mtg plate is held on with wedgloc tapered bolts and internal star washers 

that was the only time i have needed rcovery when a reputable supplier replacement had std bolts fitted which unscrewed and jammed the prop coupling

 used as the hole in the support is 7/16" and the bolt thread is 3/8unf 

Pete

[68vitesse]

14 minutes ago, Mjit said:

If they'd used set screws the full length would be threaded, so thinner and weaker.  Potentially the maths may have mean needing to go up from 3/8" to 7/16, which will be heavier/more expensive and might in turn might mean needing more metal in the diff. casting, so even more weight and money.

Don't see why a set screw would be any weaker than a bolt, as the saying goes a chain is only as strong as its weakest link.

But then more links the greater the opportunity for failure.

Regards

Paul.

 

[JohnD]

3 hours ago, 68vitesse said:

The only accessible part of the stud, until the spring is out, is the threaded portion.

Regards

Paul.

 If you're going this far in mods/renovation, then the spring is out and probably the diff too!   Like yours.   No access problem at all.

If you disagree about the stress of double nutting, then fine, but I'd rather not risk it.

 

 

I notice the end of one of your studs is slotted, as if someone has in the past replaced it 'in situ' by cutting that and using a screwdriver.   Another method that weakens the stud!

John

[68vitesse]

1 hour ago, JohnD said:

 If you're going this far in mods/renovation, then the spring is out and probably the diff too!   Like yours.   No access problem at all.

If you disagree about the stress of double nutting, then fine, but I'd rather not risk it.

 

 

I notice the end of one of your studs is slotted, as if someone has in the past replaced it 'in situ' by cutting that and using a screwdriver.   Another method that weakens the stud!

John

As said you need to remove the studs to get the spring out to remove the diff, therefore the studs are already out when you could use the stud extractor on the unthreaded portion.

If the cut is above the nut how does it weaken the stud where the strength is needed?.

Regards

Paul.

[JohnD]

Paul,

The spring comes out sideways, once the cover plate is off, no need to remove the studs. (Possibly, if it's a swing spring, it must come off vertically!)

The screwdriver will spread the stud across the slot.   mae it more difficult to get the nut, and possibly the plate on.   And of course if cut too far down, the nut will compress the slot, potentially loosening  the nut.

John

 

[68vitesse]

21 minutes ago, JohnD said:

The spring comes out sideways, once the cover plate is off, no need to remove the studs. (Possibly, if it's a swing spring, it must come off vertically!

You need to take some studs out as the bands around the spring will not pass between the two rows.

if taking half out you might as well do the rest to make it easier, less for the bands to catch on.

Regards

Paul

 

 

 

[Pete Lewis]

biggest mistake is when the garage wall wont give you the room to slide it out 

Pete

[68vitesse]

Nothing is easy, just discovered the front to back diff. case gasket, from one of the main suppliers, will not fit over the flange on the front case.

Must take a lot of effort to get wrong something so simple, probably Tuesday before supplier is open.

Quick google shows that paper gaskets can shrink due to to a loss of moisture, so might be down to storage by supplier or maker.

Regards

Paul.

 

[johny]

You could try soaking it in water for a while and then see if it then fits...

[68vitesse]

12 minutes ago, johny said:

You could try soaking it in water for a while and then see if it then fits...

Was a google solution but don't fancy fitting a wet gasket, although one person mentioned soaking drying off and using chapstick.

Pity gasket is so difficult to get to or might take the risk.

Regards

Paul

[Steve P]

I`m going to do a CV conversion on my Herald soon,part of this will be replacing the old standard original spring with a new courier one i have,with a 1" block.

Thing is,it has a 3:63 diff in a four stud casing,i have been using it like this for at least 8 years with no issues,including completing the 2014 RBRR in it.

Any thoughts?.

Steve

[JohnD]

Your 1" lowering blck will need longer studs.   Or bolts.

 

[johny]

37 minutes ago, Steve P said:

I`m going to do a CV conversion on my Herald soon,part of this will be replacing the old standard original spring with a new courier one i have,with a 1" block.

Thing is,it has a 3:63 diff in a four stud casing,i have been using it like this for at least 8 years with no issues,including completing the 2014 RBRR in it.

Any thoughts?.

Steve

Its a bit of a mystery why Triumph saw fit to have the six fixings although it looks like it was to reinforce against the levering action of the spring when one wheel hits a bump. The swing spring then couldnt have the 6 but also because of the rocking action the forces are probably less...

Although Ive never heard of a failure of the diff casing through using it as you have previously I would have thought the courier spring will only increase the forces applied so maybe a step too far. You could change the case or drill/tap it to have the six fixings and install a drain plug at the same time👍   

[Pete Lewis]

i had a 4 holediff when i changed the diff and went for a swinger , that was hopeless and a courier and 1" packer replaced it 

i used the spring clamp plate as a drill jig and with a battery drill   drilled 8,3mm  for around 25mm deep and tapped 3/8" x24 unf to add the missing two stub holes  was an  easy fix 

with the stiffness of the courier spring 4 studs might be pushing your luck a bit

Pete

 

[68vitesse]

I drove my Mk1 2L Vitesse for years with a four stud diff without any problems.

1 hour ago, JohnD said:

Your 1" lowering blck will need longer studs.   Or bolts.

 

Looking into using bolts with Nord-Lock washers with the ½in. lowering block I have and with my spring need four inch bolts which have a 1in. threaded length, standard seems to be twice the diameter plus a quarter.

Currently waiting for the diff. gasket to dry to see if it fits.

Regards

Paul

[dave.vitesse]

Studs are used instead of bolts because it lowers stress on the diff threads when you torque the spring down. Also it give better security to the fixing. Six hole fixing gives better rigidity than four hole fixing.

Dave

[Pete Lewis]

and with a 1" the studs or  if you use bolts can foul the cover plate, makes a lovely racket  

i covered mine with a thick rubber mud flap , Bill at rarebits4 made some deeper covers but alas not now .

Pete

 

[68vitesse]

2 hours ago, 68vitesse said:

Currently waiting for the diff. gasket to dry to see if it fits.

Stupid idea, now smaller than when I started so looks like I might install it wet.

Regards

Paul

[68vitesse]

Phoned the supplier of the diff. gasket today, got the standard answer no one else has complained, so my diff. is a different size to everyone elses.

Should have taken a photograph while it was apart.

Regards

Paul.

[Colin Lindsay]

On 03/04/2021 at 10:03, 68vitesse said:

Nothing is easy, just discovered the front to back diff. case gasket, from one of the main suppliers, will not fit over the flange on the front case.

Mine must have come form the same supplier, but it tore when I tried to slide it over the side of the case with the 'lip'... luckily I had a spare and soaked it well in diff oil beforehand. That made it more pliable and it fitted without damage.

[Steve P]

On 03/04/2021 at 16:00, Pete Lewis said:

Bill at rarebits4 made some deeper covers but alas not now .

I have one of his last ones on the shelf,he had a few not trimmed around the edges so i got one.

Steve

[68vitesse]

2 hours ago, Colin Lindsay said:

Mine must have come form the same supplier, but it tore when I tried to slide it over the side of the case with the 'lip'... luckily I had a spare and soaked it well in diff oil beforehand. That made it more pliable and it fitted without damage.

Did you contact the supplier about the problem?.

Luckily I had a sheet of 0.25mm gasket paper so ended up making one.

Regards

Paul