Brumby rear torsion bar pretension

SuBaRiNo · Post by **SuBaRiNo** » Thu May 29, 2014 9:53 pm

Hey guys... Hopefully someone can help me... I'm sure over the past 10 years someone put up some instructions on how to preload/pretension the rear torsion bar in an MY wagon/brumby. I can't for the life of me seam to find it.

Hopefully people get what I mean by preloading.

Procedure was something like.... Wind adjuster all the way out (lowered position)... Jack up back of car so rear wheels were off the ground... Remove each arm off torsion bar.... Do something.... Do something..... Do something... And most importantly do something.

Dave

AndrewT · Post by **AndrewT** » Thu May 29, 2014 11:45 pm

Why am I visualizing a gnome with a huge beard saying "phase 1: adjust brumby suspension, phase2:.......phase3: profit!" ?

I found a bit of info here...
archive/index.php/t-21444.html

I remember adjusting that big bolt a bit tighter for extra lift when I had wackybug but didn't go as far as undoing anything else.

RSR 555 · Post by **RSR 555** » Fri May 30, 2014 8:04 am

What are you trying to achieve? What did you do on Hatchie?

steptoe · Post by **steptoe** » Fri May 30, 2014 8:27 am

Hatchie is not a Brumby is it ??
From factory , MY, or rather MV Brumbies have 20mm clearance between bump stop and its stop point. Saw this and gave up on the idea of lowering a Brumbys bum, butt, saw a low-as-f Brumby the other day, would love to have seen under it. Reckon he must grade his driveway with micro precision, or park it at the gate !

RSR 555 · Post by **RSR 555** » Fri May 30, 2014 8:36 am

I thought you knew what Hatchie was??

Same torsion arm and really doubt Dave is lowering it

SuBaRiNo · Post by **SuBaRiNo** » Fri May 30, 2014 9:02 am

To keep it brief... Rear end of brumby is sagging. This isn't my first MY style rear end. Hatchie has an inch smaller lift in the back than the front and the torsion bar is adjusted to make it level. This thing has the same lift all the way around and with the torsion bar wound all the way up (bolt in) it's still barely level with nothing in the tray.

This tells me the torsion bar is worn and I want to "retention" it (lack of a better word) I have heard of this being done... A long time ago. By shifting the side arms down a spline or 2 on the torsion bar.. Hoped someone might know what I was on about but I might have to experiment.

Dave

RSR 555 · Post by **RSR 555** » Fri May 30, 2014 9:25 am

It can be done but you need to make sure you have all the tension off, so best to drop the bottom bolt off the shockes before you undo the Torsion Bar. Loosen the Torsion Bar Bolt (but don't remove it) then remove the 3 bolts holding the Torsion Bar Arm to the Rear Control Arm. Once this is all done, then you can mark the position of the Torsion Arm and then remove the Torsion Bar Bolt. Then you can tap the Torsion Arm off and reposition it.

Another option is to fit L.Series rear shockes which is better option if you plan on carrying any loads

Nubaru · Post by **Nubaru** » Fri May 30, 2014 4:35 pm

I am wondering who put the idea in my head of L series rear shockies in a MY Brumby.
What are they ..45-50mm dia of original shock. L shock much the same, but you mean to add the shock and coil spring too ? I don't know what sort of MY you have been able to fit L shockers and their springs to if that is the case, there is barely a non Tongan finger space between the shock and skin of rear tub, let alone a spring!

The top mount between L and MY at rear shock is waaaay different too, won't just bolt up. L shocks trown away

Post by **TOONGA** » Fri May 30, 2014 6:23 pm

this page from my brumby build may help

showpost.php?p=166246&postcount=593

I currently have vortex rear shocks in my brumby they fit and make it way easier to cart stuff around

While the post shows MX5 shocks being put in place the first picture is of an "L" shock in place

this post shows the vortex shocks in place

showpost.php?p=224458&postcount=665

TOONGA

RSR 555 · Post by **RSR 555** » Fri May 30, 2014 7:00 pm

Nubaru wrote:I am wondering who put the idea in my head of L series rear shockies in a MY Brumby.
What are they ..45-50mm dia of original shock. L shock much the same, but you mean to add the shock and coil spring too ? I don't know what sort of MY you have been able to fit L shockers and their springs to if that is the case, there is barely a non Tongan finger space between the shock and skin of rear tub, let alone a spring!

The top mount between L and MY at rear shock is waaaay different too, won't just bolt up. L shocks trown away

The L.Series almost complete rear shock including spring will fit in. I have done this many times. You need to swap over the top bracket so it fits the Brumby body or you can make one like the one we did for TOONGA's Brumby. All depends if you have a lift kit or not.

Personally I have Monroe Air Shockies in the back of my MY wagon which about the same diameter as the L.Series spring and these can be adjusted according to loads

Nubaru · Post by **Nubaru** » Fri May 30, 2014 10:03 pm

maybe I should have tried a little harder

Silverbullet · Post by **Silverbullet** » Fri May 30, 2014 11:03 pm

Is it not a bit dangerous mounting L series shocks and springs on the old MY wheel tubs? Not being designed for that amount of stress.

RSR 555 · Post by **RSR 555** » Sat May 31, 2014 5:04 am

Nubaru wrote: maybe I should have tried a little harder

LOL.. maybe but really doesn't take much effort

Silverbullet wrote:Is it not a bit dangerous mounting L series shocks and springs on the old MY wheel tubs? Not being designed for that amount of stress.

Not at all. As you can see in one of TOONGA's posts that there is a body stiffening section that runs up from the main monocoque frame. These 'coil over' macpherson strut design was used in this configuration on the early rally cars, albiet some seam welding involved but this was move to stop body flex over the whole vehicle.

SuBaRiNo · Post by **SuBaRiNo** » Sat May 31, 2014 9:40 am

Thanks guys. Due to an unbelievably tight budget I don't think I will be able to change to L series rear shocks.... But I have since found in one of my books what I was after. (yes one of those things with the paper inside)

There is a procedure to adjust the height for a 2wd model that does not have the height adjustment bolt... I feel this will help spring the rear back to life (pun intended). The method described by Paul is basically right though. Apparently tooth rotated on the torsion spline will lift it 7cm.

Dave

Dave

Post by **TOONGA** » Sat May 31, 2014 9:46 am

Dave I have a set of "L" shocks in the shed you can have.

As well Im sure RSR will have a set collecting dust he may want to donate.

All you need is the top bracket and a spacer bar.

TOONGA