Advice re my IRS set up & lowering it please.

Post Reply
ernie
Registered user
Posts: 1169
Joined: Wed Sep 02, 2009 6:20 pm

Advice re my IRS set up & lowering it please.

Post by ernie »

Hi all,

Just bought a bus with IRS already fitted, but it was stock height.

I've lowered the front by fitting a new beam, so now I need to lower the back by about 3-4 inches.

Below are some photos which will hopefully give you some idea of my IRS set up..

Image

Image

Image

Image

The gearbox code is DC which I believe is type 3.

My questions are as follows:

Can anyone identify what set up I currently have - it looks to me like the boxwagen kit which bolts onto the axle tube, and I assume the A arms are beetle or early bay??

One of the allen headed bolts which attach the A arms to the axle tube clamps does not appear to be threaded into the threaded end enough - I assume that I can just turn this bolt in more to get better purchase in the thread?

What is the easiest way to lower the back end?

I assume I could just turn the spring plates on the outer splines 2 notches to get around a 4 inch drop, but someone mentioned that boomerang plates just bolt onto the spring plates without having to rotate them and they lift the hub up to retain the same ride quality, but would boomerang plates work with my set up? I would probably prefer this option if possible as it appears to be the easiest?

Also, if boomerang plates would not work with my set up, and I turned the spring plates, would I have to undo/rotate the clamps around the axle tube to retain the geometry?

Any advice/suggestions gratefully received.

Many thanks.

ernie
Registered user
Posts: 1169
Joined: Wed Sep 02, 2009 6:20 pm

Re: Advice re my IRS set up & lowering it please.

Post by ernie »

More info - just taken a rear wheel off to get a better look at the spring plate set up...

Image

The spring plate looks quite small and has just 2 holes in it where it bolts to the hub carrier (least I think that's what it's called!), but the hub carrier has 4 holes in it, so only 2 of them are utilised - when I get it sorted, may drill at least another hole in the spring plate to ensure I have at least 3 bolts.

Looking at the spring plate, it doesn't look like the Boomerang plates will fit as they have 4 holes where the hub carrier bolts to the spring plate?

Also, the bolts that hold the wheel on look a bit small to me - the thread length is about 1/2 inch, with 5 revolutions before they are tight - does this sound right - although I'm looking for some alloys so will fit longer bolts then, assuming I need to?

Image

Advice, please.... :roll:

thesickness
Registered user
Posts: 459
Joined: Sun Nov 28, 2010 8:30 pm

Re: Advice re my IRS set up & lowering it please.

Post by thesickness »

As you haven't got any replies I'll try and help as I IRS'd my bus myself but am not familiar with some parts you have so I'll say what I see.
DC code box is a good choice as it's the same code as an AH so good for engines 1500-1776.
Bolt on clamps could be boxwagen but they look horribly twisted and out of shape.
From what I can see, if the bus is sitting on floor when you took the photo from rear (tyre on floor) looks like you're going to get clearance issues on the cradle if you haven't already.
Springplates don't look right at all, look like they've been cut to allow travel and bolted on with 2 bolts isn't right.

Personally depending on budget, I would think about getting earlybay hardware off mattp on here (drums, hubs, stubaxles) get a pair of creative adjustable springplates, find out if your clamps are actually boxwagen if so get a pair of short a arms from him and bobs your uncle. Should be a shopping list of around £1200.
Your set-up could be busboys or something using all beetle parts.
As said get further advice, it's should be along but it's very quiet on here at the moment, try also the ssvc facebook group , you should get fairly quick advice on there....Also book that i cant remember the title of, how to modify your vw bus or something....red bus on front...Is a great read as it explores most lowering systems....Hope this helps.

thesickness
Registered user
Posts: 459
Joined: Sun Nov 28, 2010 8:30 pm

Re: Advice re my IRS set up & lowering it please.

Post by thesickness »

Also it looks like your brake pipe is dangerously close to the cradle and corroded!

dweeb
Registered user
Posts: 161
Joined: Tue Oct 10, 2006 2:06 pm

Re: Advice re my IRS set up & lowering it please.

Post by dweeb »

99% certain Bugbox type 1 IRS kit, shock mount / bump stops are the same as mine. Bolt on brackets look ok to me, I drilled a third hole in the spring plates for extra security.

I believe T2D used to sell the kit before bring out their own version.

I bough mine directly from Walter at Bugbox, migh be worth having a look on their website.

Allen bolts might be able to be wound in a bit further but it might be worth taking them out to check the threads are ok.

As far as lowereing is concerned unbolt the spring plate from the A arm and rotate it as many notches as you need.

pokey
SSVC Member
SSVC Member
Posts: 893
Joined: Tue Jul 08, 2008 4:27 pm
Location: north wales

Re: Advice re my IRS set up & lowering it please.

Post by pokey »

i don't see why would would want to change to early bay? The spring plates do look pants id stick some adjustable ones on there, or as you said drill your existing ones

ernie
Registered user
Posts: 1169
Joined: Wed Sep 02, 2009 6:20 pm

Re: Advice re my IRS set up & lowering it please.

Post by ernie »

Many thanks for the info guys - yes, looking at the BugBox web site, it does look like their kit, although I can't seem to find out much from their website - does anyone know if any dealers in the UK sell this kit?

The IRS kit seems to come with the spring plates, so are they likely to be bespoke BugBox items, or possibly beetle/type 3?

Just wondering what spring plates I would need to buy if I were to get lowered ones - Not sure about adjustable springplates as doesn't the whole of the weight of the rear of the bus rest on the little welded block?

If I turn the existing spring plates on the splines, would I have to rotate the clamp on the axle tube? And also, how do I pull the spring plates off the splines with the A arms in place?

Any advice gratefully appreciated as I am new to lowering IRS.

Thanks
Last edited by ernie on Wed Oct 15, 2014 5:24 pm, edited 1 time in total.

User avatar
vwJim
SSVC Committee Member
SSVC Committee Member
Posts: 19981
Joined: Thu Apr 24, 2003 6:05 pm
Location: under a bus in Hampshire...
Contact:

Re: Advice re my IRS set up & lowering it please.

Post by vwJim »

dweeb wrote:99% certain Bugbox type 1 IRS kit, shock mount / bump stops are the same as mine. Bolt on brackets look ok to me, I drilled a third hole in the spring plates for extra security.

I believe T2D used to sell the kit before bring out their own version.

I bough mine directly from Walter at Bugbox, migh be worth having a look on their website.

Allen bolts might be able to be wound in a bit further but it might be worth taking them out to check the threads are ok.

As far as lowereing is concerned unbolt the spring plate from the A arm and rotate it as many notches as you need.
Certainly looks like a badly fitted BugBox kit, or rather half a kit.

The spring plates are presumably home made, as BugBox would not supply them like that.
Spring plates are always bolted up with a minimum of three bolts.
The upper shock mount doubles up as bump stop mount, but the A-arms don't have any bump stop rubbers fitted.


Yes, if you dropped the splines around it would lower it, then you redial in the camber by adjusting the bolt on bracket on the main torsion tube. And tracking, (assuming the spring plates are slotted), by moving the A-arm relative to the spring plate.

Probably worth getting new spring plates if you can't machine in slots and the third hole. You don't "need" adjustable spring plates, but they do make life easier in most cases unless you run stock wheels then they can cause clearance issues.
Supplying quality in house designed items plus parts from SyncLink, Kennedy Clutches, & CB Performance. Also fitting service including modifications & mechanical upgrades.

User avatar
vwJim
SSVC Committee Member
SSVC Committee Member
Posts: 19981
Joined: Thu Apr 24, 2003 6:05 pm
Location: under a bus in Hampshire...
Contact:

Re: Advice re my IRS set up & lowering it please.

Post by vwJim »

That wheel bolt looks like a Beetle bolt, so assume you have T1 rear brakes using steel wheels.

Boomerang plates are for the T2 based IRS systems, not T1 based.
Supplying quality in house designed items plus parts from SyncLink, Kennedy Clutches, & CB Performance. Also fitting service including modifications & mechanical upgrades.

ernie
Registered user
Posts: 1169
Joined: Wed Sep 02, 2009 6:20 pm

Re: Advice re my IRS set up & lowering it please.

Post by ernie »

Many thanks guys - may just take it all apart, paint it up and see what I am working with - I assume I could use Beetle adjustable spring plates, or possibly these fixed lowering ones from Red9..

http://www.red9design.co.uk/DSC00426_2.jpg

I am intending to run 5.5in ch BRMs or possibly Empi 5's, so am I likely to get issues with removing the rear wheels if I drop it 2 notches unless I use adjustable spring plates (2 notches = around 4 inches?).

cheers

User avatar
vwJim
SSVC Committee Member
SSVC Committee Member
Posts: 19981
Joined: Thu Apr 24, 2003 6:05 pm
Location: under a bus in Hampshire...
Contact:

Re: Advice re my IRS set up & lowering it please.

Post by vwJim »

No, you own a bus, so they have to be bus spring plates, suitable for T1 A-arms.

Probably, though it depends on the year of the bus and the width / profile of tyre
Supplying quality in house designed items plus parts from SyncLink, Kennedy Clutches, & CB Performance. Also fitting service including modifications & mechanical upgrades.

User avatar
vwJim
SSVC Committee Member
SSVC Committee Member
Posts: 19981
Joined: Thu Apr 24, 2003 6:05 pm
Location: under a bus in Hampshire...
Contact:

Re: Advice re my IRS set up & lowering it please.

Post by vwJim »

PS the CV's will probably like you to lower the bus as they're working at quite an angle there.
Supplying quality in house designed items plus parts from SyncLink, Kennedy Clutches, & CB Performance. Also fitting service including modifications & mechanical upgrades.

Post Reply