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Pastormajorquin 02-11-2021 11:22 AM

Thread size rear Spring Adjuster
Who knows the threadsize of the rear Spring Adjuster?
I got a new KW-Suspension System fully adjustable and saw that the rear thread was a little bit defect!
Thanks for help!

spdbrake 02-11-2021 02:49 PM

The spanner nuts will clean (restore) the threads once thru the rough area once or twice. You need to lube the threads while doing this. A small jeweler file (triangle shape) will clean up deformities. A Mallet and an old flat-tip screwdriver or a bronze punch will coax the nut thru those areas.

If you have a metric Tap and Die set the included thread pitch gage will tell you the pitch per mm and you can purchase a thread file like this.

However you mentioned a fully adjustable KW suspension. Is that new shocks or rear coilovers, ditching the current rear springs and perches?

Kobura 02-11-2021 10:51 PM

I had to use a die nut/rethreading die to chase all of the threads on the post after removing the height adjuster which was stuck/cross-threaded on the post. I do not remember what size the die was, but I remember how tedious it was to wrench the adjuster nut and the die about a third of a turn at a time because of the limited space in which to work. I borrowed the die from the BDR dealer as a warranty deal.

I sure would like to read more about your new suspension parts.

SGwick 03-18-2021 04:34 PM


Originally Posted by Pastormajorquin (Post 1488971)
Who knows the threadsize of the rear Spring Adjuster?
I got a new KW-Suspension System fully adjustable and saw that the rear thread was a little bit defect!
Thanks for help!

KW variant 3 system?

spdbrake 03-18-2021 05:22 PM

I see the OP has been on lately and I'm still hoping that they share some details on the suspension they purchased.

SGwick 03-18-2021 06:55 PM

spdbrake, do you know anyone that has installed KW variant 3 or Ohlins road & track suspension on a Backdraft? Thoughts?

spdbrake 03-18-2021 07:10 PM

There’s only one BDR owner that frequents this site that has what I’d call a modified suspension as he auto crosses. Screen name: Grey65. For your car being an RT4 I’d check with Jay as the suspension is totally different I’m told than the Rt2 / Rt3 models.

SGwick 03-18-2021 07:31 PM

thanks boss, waiting for the car I end up looking more lol

its a vicious circle :-)

Phil988 03-20-2021 07:41 AM

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I also got an KW V3 suspension system for my Backdraft. Unfortunately I can not share any driving impressions with you, as the car is still under construction :)

Phil988 03-20-2021 07:43 AM

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Here is the rest of the photos. Feel free to ask if you have any questions.

Greetings from Germany,

spdbrake 03-20-2021 09:01 PM

Thanks Phil, That looks like a quality setup. I see you have an RT3. What build #?
Also what is the part number of the kit?

I'm curious on the rear coil-over attachments. Are they in single shear like the stock shocks?

Phil988 03-21-2021 12:30 AM

Yes its a RT3, according to Iconic Parts it should be #510.
The part no. is 39500000, but I doubt you can order it with this number, as according to google it is used for different KW kits. You can refer to my order no. which is 1220050.

Yes the rear coil-overs are in single shear, like the standard ones.

spdbrake 03-21-2021 06:22 AM

Thanks Phil, I had / have been tossing around the idea for going with a Wise Fab Rally suspension, axles. Yes its overkill but that's not the point.

I do like that Wisefab has rebuild parts available.

So far I've only changed all the Front and Rear suspension parts with new OEM and Poly bushing everywhere, springs, camber plates, shocks and added Powerflex rear lower control arms.

I am really curious what the RT4 rear suspension actually looks like as I'd really like to go to the Ford 8.8 IRS.

Phil988 03-21-2021 06:30 AM

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Really nice! But quite costly as well.
I've gone for a complete (Euro spec) E36 M3 rear axle with the big 210 diff that also got rebuilt and customized. Adjustable camber arms and poly bushings all around.

spdbrake 03-21-2021 07:19 AM

That looks great. I probably should have gone that route at the beginning before installing new axles, and driveshaft. From the case size it looks like I'd have to modify both.

I was leaning towards Racing Diffs out of Serbia but don't have any hard info on their quality yet. Still digging.

Phil988 03-21-2021 12:36 PM

Yes both parts are different with the M3 rear axle. Chassis wise the handbrake cable bracket and routing has to be changed.

Don't you have (BMW) diff service workshops in the states? I got mine with a 3,62 ratio, 60/30% lock and pre-loaded.

spdbrake 03-21-2021 03:19 PM

I had considered just doing it my self as the operation is simple but the LSD unit pushes $1.7k itself with out bearings, seals etc...(Mine is an Open rear) I may still do that as I hate to farm out work. This car is wrench time therapy for me since I don't actually turn wrenches anymore.
There are shops but are pricey @ $2.5k+ and shipping mine out or eat a $400 core charge.
The E36 diffs are all roughly 25+ years old thus my attraction to the Ford 8.8. Much cheaper to work on and not scarce.
I do admit the Open diff does keep me out of the ditch or jumping a curb though.

SGwick 03-26-2021 03:33 PM


spdbrake 03-26-2021 03:49 PM

You can send him a PM here

Pastormajorquin 03-30-2021 02:35 PM

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Originally Posted by spdbrake (Post 1490457)
I see the OP has been on lately and I'm still hoping that they share some details on the suspension they purchased.

I am sorry spdbrake for the delay in telling you more about the KW fully adjustable suspension set up!
Phil an I just purchased the KW System and it is a motorsport specialy developed for backdraft. The car feels more stable and safer. You can also setup the bump and rebound. I left it on the settings that KW tested it. It is a competition suspension and not a standard suspension. You have to get in contact with the race division from KW-Suspension.

If you need more infos, just write me.


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