The Brick-yard Homepage Brickwerks
Forum Home Forum Home > LT, Crafter & Sprinter Section > LT, Crafter & Sprinter Tech
  New Posts New Posts RSS Feed - LT (S1) Rear Suspension Lowering
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Topic ClosedLT (S1) Rear Suspension Lowering

 Post Reply Post Reply
Author
Message
 Rating: Topic Rating: 1 Votes, Average 5.00  Topic Search Topic Search  Topic Options Topic Options
TwoSheds View Drop Down
Groupie
Groupie
Avatar

Joined: 02 Oct 09
Location: Manchester
Status: Offline
Points: 167
Direct Link To This Post Topic: LT (S1) Rear Suspension Lowering
    Posted: 25 Jun 10 at 09:21

I have an 1995 Lt45 Camper which ( being rated at 4600kg loaded ) sat very high at the rear. Not only did this look wierd on a camper but needed site levelling on a flat surface.

I lowered it by ( if my memory serves me correctly ) 65mm by removing all of the springs except for the main one and adding the short bottom spring off my old 76 LT35 ( smaller diameter leaf bolt ). The resulting ride height was just about perfect but needed to be "Assisted" for additional loads ( rear storage box, bike trailer etc. ) and bumpy surfaces. The VW Spring Assisters were/are a ridiculous cost and I investigated adding Air Bags but there is no reasonable room on the late twin rear axles so decided to put "assisters" on search ( eBay ) until something came up.
 
I found some rubber assisters on ebay 2 weeks ago ( current quantity Listing 3601 1472 6168 ) for £42.44 delivered ( big saving ) and these have worked out very well. Just needed to trim them to the right length for my van and fit them to the existing correct position. These assisters are actually truck units ( bump stops ) but they give a very good ride ( they have been trimmed so that they are always in operation ) with good control over speed bumps.
 
A bigger problem was re-working the load compensator. With lowering, the load spring was under high tension on minimum setting allowing too much pressure to the rear brakes. Unfortunately, different springs  ( mine is 6.5mm x 270mm and I wanted 4mm x 278mm ) from VW ( only source ) are on "Back Order" ( not yet obsolete?? ) so I have to make a suitable hook extension to allow me to set a reasonable base pressure on the rear axle.
 
As often happens; it does not stop there ( pardon the pun ) as special tools are required to both adjust the spring tension accurately and monitor the hydraulic pressure rate of the rear axle whilst adjusting. I made a stirrup adjustment tool to allow me to finely increment the adjustment and made a pressure gauge set that connects to one of the slave cylinder supply pipes.
 
Anyone who has considered lowering the rear of an LT45 may have given up when the full cost of the procedure has been calculated. The load sensor spring being the biggest problem because you can only cross reference LT28/31 with LT 35/45 pressure rates  ( you have to consider the resulting perameters of your new suspension set-up ) and take a stab at the base pressure setting - which I have chosen at 65bar ( reassessed to 80Bar and soon to be re-adjusted to around 40Bar - Adjust and test until the rear does not lock-up prematurly ). Trying to get a Main Dealer Workshop to perform the setting-up would be a non-starter as there are no definative figures for modified vehicles, or kits, for them to work with.
 
As I have taken the trouble to make the kit I am willing to hire the kit out to anyone who wants to recalibrate their rear brakes.


Edited by TwoSheds - 09 Jul 10 at 07:45
Back to Top
mat_the_cat View Drop Down
Vanorak
Vanorak
Avatar

Joined: 06 May 09
Location: North Wales
Status: Offline
Points: 1862
Direct Link To This Post Posted: 25 Jun 10 at 11:52
Just one thought that may simplify your task - being a camper the weight you will be carrying will (presumably) remain fairly constant. Therefore, do you actually need an automatic compensator at all, and would a simple brake bias adjuster do the trick? Not sure on the legality but may be worth some thought.
Mid engined, 6 cylinder, turbocharged 2 seater - it can only be a VW LT!
Back to Top
TwoSheds View Drop Down
Groupie
Groupie
Avatar

Joined: 02 Oct 09
Location: Manchester
Status: Offline
Points: 167
Direct Link To This Post Posted: 25 Jun 10 at 13:09
Hi MTC.
Thanks for your thoughts but the job is not more complicated (?) than it needs/has to be. Construction rules apply : If it had a compensator, ex works, then it must have a compensator. There are enough problems with MOT testers attempting a fail because "The Van is on it's Bump Stops"  ----HoHum.
 
I considered a simplified reg. valve but decided that it would, potentially, be more work especially when you get to construction, approval, mfr's waivers, insurance, VOSA and Engineers reports --------- but most people don't consider these things.
 
There is also the subject of revised loading so I am likely - once the job is done and I am happy with it - to get the rear of the van weighed and go for a re-rating ( Did VW ever do an LT32.75?? ) as it is no longer anything more than an LT35.
 
Cheers


Edited by TwoSheds - 09 Jul 10 at 16:26
Back to Top
mat_the_cat View Drop Down
Vanorak
Vanorak
Avatar

Joined: 06 May 09
Location: North Wales
Status: Offline
Points: 1862
Direct Link To This Post Posted: 25 Jun 10 at 15:58
I'd wondered whether red tape would get in the way - good luck anyway!
Mid engined, 6 cylinder, turbocharged 2 seater - it can only be a VW LT!
Back to Top
Tazz-man View Drop Down
Groupie
Groupie
Avatar

Joined: 23 Mar 10
Location: Hastings UK
Status: Offline
Points: 65
Direct Link To This Post Posted: 26 Jun 10 at 19:53
Interesting read
Tazz-man VW LT 31, 1981-82, Y Reg, HighTop Homebuilt Camper
Back to Top
Nyquist View Drop Down
Newbie
Newbie


Joined: 08 Jul 10
Location: Newport
Status: Offline
Points: 5
Direct Link To This Post Posted: 08 Jul 10 at 20:49
& there's me thinking it was going to be a simple axel flip like a mk1 caddy!

don't happen to know if it's possible to buy coilovers for the front end do you?
Back to Top
The_blue View Drop Down
Groupie
Groupie
Avatar

Joined: 12 Mar 07
Location: Mansfield-ish
Status: Offline
Points: 107
Direct Link To This Post Posted: 08 Jul 10 at 21:22
Originally posted by TwoSheds TwoSheds wrote:

The Van is on it's Bump Stops
 
Hmmm.. was just looking at that on mine. Is that normal on the front? I'd assumed i was in for pain at the MOT because the last owner had done something.
 
Good thread though. mines about 5 inches higher at the back. Campsites folk look gone out when i head for a slope to level it on Wacko
Back to Top
TwoSheds View Drop Down
Groupie
Groupie
Avatar

Joined: 02 Oct 09
Location: Manchester
Status: Offline
Points: 167
Direct Link To This Post Posted: 08 Jul 10 at 23:13
Hi Nyquist and The-blue

I finished the re-calibration on my rear axle and it worked very well excepting that I need to lower the base pressure to about 40-45Bar ( the rear still wants to lock-up on full breaking ).

I have pictures of the new suspension, the adjusting tool and pressure monitor if anyone is interested.

As Nyquist asks about "Coil-overs"  the van is an LT35 (or lower)  and a droopy front is completely normal with age. New coils will normally bring the van up level ( I did this on my LT35 - twin rears and it came level ).
 
The only vans that sit high at the rear from new are Lt45-55.
 
To compound the problem : An LT35 twin rears can have HD springs at the rear making it high and tired coils at the front making it low.
 
General conclusion for me is if you have coils at the front and your van is high at the back then replace the coils.


Edited by TwoSheds - 09 Jul 10 at 16:29
Back to Top
Nyquist View Drop Down
Newbie
Newbie


Joined: 08 Jul 10
Location: Newport
Status: Offline
Points: 5
Direct Link To This Post Posted: 09 Jul 10 at 00:21
Thanks for the info TwoSheds, be good to see the photo's definitely. i actually want to lower the whole van (mines an 86 LT35 twin rears) but don't really know where to start! front end is much lower than the rear though just like you said..the aim is basically to slam it as low as possible..
1986 LT35 2.4TD SWB Twin Wheel High Top
Back to Top
TwoSheds View Drop Down
Groupie
Groupie
Avatar

Joined: 02 Oct 09
Location: Manchester
Status: Offline
Points: 167
Direct Link To This Post Posted: 09 Jul 10 at 07:19
Morning Nyquist
 
If you are wanting a low rider then all of the usual considerations apply : Driveabilty, handling, safety and load reaction. The rear dictates how low you can go if you want the finished result to be level. There are either 2 or 3 leafs on the rear. If there are 2 then there is not much that you can do but if there are 3 then the middle spring could be removed and a trimmed to length Rubber Spring Assister fitted. To me, this is as far as is sensible. Alternatively you could fit LT28 front coils ( old tired ones ) and investigate swopping your rear springs for LT28 but there is a possibility that the spring lengths ( main spring ) are different between single/twin rear set-ups. There is  a difference in fixing bolts diameter but I don't know if this is just model or model&year specific.


Edited by TwoSheds - 09 Jul 10 at 07:19
Back to Top
TwoSheds View Drop Down
Groupie
Groupie
Avatar

Joined: 02 Oct 09
Location: Manchester
Status: Offline
Points: 167
Direct Link To This Post Posted: 09 Jul 10 at 07:46
Please re-read the first post as I have updated the narrative.
Back to Top
Nyquist View Drop Down
Newbie
Newbie


Joined: 08 Jul 10
Location: Newport
Status: Offline
Points: 5
Direct Link To This Post Posted: 09 Jul 10 at 10:31
TwoSheds once again thanks a lot for the info Smile can see this is going to take a fair bit of investigation/planning!
1986 LT35 2.4TD SWB Twin Wheel High Top
Back to Top
TwoSheds View Drop Down
Groupie
Groupie
Avatar

Joined: 02 Oct 09
Location: Manchester
Status: Offline
Points: 167
Direct Link To This Post Posted: 09 Jul 10 at 10:45
Hi Nyquist
Despite much assessement and planning Sh-t still happens and it's a"Chunky Number" removing the springs only to find that your fixings don't work. Not so bad for me as I have thousands of fixings and lots of material/machinery but for those with limited or no workshop facilities these jobs can be a bitch!!
If you are to swop spring leafs on a late van with early ones then you need a smaller diameter assembly bolt ( HT Allen bolt ) with a bush for the leaf with a larger hole.
 


Edited by TwoSheds - 09 Jul 10 at 10:49
Back to Top
The_blue View Drop Down
Groupie
Groupie
Avatar

Joined: 12 Mar 07
Location: Mansfield-ish
Status: Offline
Points: 107
Direct Link To This Post Posted: 09 Jul 10 at 12:08
Originally posted by TwoSheds TwoSheds wrote:

 droopy front is completely normal with age.
 
 
Thought that would be it. Is it an MOT issue? nearside just touches the bump. Off is about 10mm off with no one sat in it.
 
Ride feels fine and it handles wind far better than the 82 T3. :)
Moving to Team Talbot :O
Back to Top
TwoSheds View Drop Down
Groupie
Groupie
Avatar

Joined: 02 Oct 09
Location: Manchester
Status: Offline
Points: 167
Direct Link To This Post Posted: 09 Jul 10 at 12:21
Mornin The-blue
Normally ( but not all Testers are normal????? ) the rule is : If it ain't on the bumps it's a Pass. So your van looks like a fail. Talking about the front of course.


Edited by TwoSheds - 09 Jul 10 at 16:26
Back to Top
Benzsc1 View Drop Down
Groupie
Groupie
Avatar

Joined: 27 Apr 09
Location: Essex
Status: Offline
Points: 204
Direct Link To This Post Posted: 09 Jul 10 at 15:27
There is only linited room between the bump stops and the springs on a standard LT anyway so cutting the bumpstops may give you enough clearance. Plus it depends what you want to use the van for if you are slamming it for shows etc then not really a prob if you are slamming it but still want to pick up 1 ton of bricks then you really need to plan it out. As Two sheds has stated drivability will be affected I am having some shorter coils made up for mine at £60 per spring untestted so I cannot answer any qeustions about how she drives yet but essentially the springs will be wound at to provide the smae spring rate as I have but will reduce the distance between the cab step and the floor but should hopefully not change the drivability to much ;)
 
Two sheds top post mate I have been looking for this type of info for a long while but decided its easier if I just experiment on my own truck seeing as I have the tools and facilties to work on her!
Mission: extract as much power as possible out of the slowest diesel engine ever Produced!!
Back to Top
TwoSheds View Drop Down
Groupie
Groupie
Avatar

Joined: 02 Oct 09
Location: Manchester
Status: Offline
Points: 167
Direct Link To This Post Posted: 09 Jul 10 at 16:25
Hi Benzsc1
If I recall; there is a Seller on eBay Germany who does 2 spring rates for coil LTs - or it may be on the German LT forum ----- too tired to be bothered looking at the mo. : Senior Moments and afternoon kips are mandatory for me - must be at THAT age.
Thanks for the compliment!
Back to Top
Benzsc1 View Drop Down
Groupie
Groupie
Avatar

Joined: 27 Apr 09
Location: Essex
Status: Offline
Points: 204
Direct Link To This Post Posted: 12 Jul 10 at 11:28
No worries mate its good to have some usefull and meaningful posting not to say all other posts are garbage but this one appeals to my can't stop tinkering nature lol.
 
I will have a scout round German ebay. In terms of senior moments and afternoon kips I believe I often feel that way and actually quite like it TBH lol
Mission: extract as much power as possible out of the slowest diesel engine ever Produced!!
Back to Top
 Post Reply Post Reply
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.01
Copyright ©2001-2018 Web Wiz Ltd.

The WebThis site