944 aluminum rear trailing arm info

[Superman]

Okay here's the scoop on 944 aluminum rear trailing arms. First off, throw the part number, year, and model out the window. Every source says something different. It's very confusing and I've never figured out the "code" yet. The best thing to do is just look at the arm, there are two versions. In the pic attached the top version is "early" and the other is "late". These are terms I have used and may not apply. Anyhoot, just look for the arch as pointed to in the bottom arm and you'll know this is the wider of the two versions.

Early (top) will widen track by 43mm
Late (bottom) will widen track by 74mm

Credit: pics and info from the book Kafer Tuning by Helmut Horn

[Superman]

Note: my reference to the terms "early" and "late" are for the 86-91 944 & 92-95 968 as applies to these rear arms. Don't confuse the 'early' reference to be meant as the 83-85 944 with steel rear arms.

[Alex]

Awesome James!

This will finally clear some things up.

Alex

[kiwivw]

Yes, thanks James.

As they say, a picture is worth a 1000 words.
This clears it up once and for all.

[Bugnutz]

All,

This is my first post to the forum.

I bought some 944 trailing arms from a Porsche dismantler.
I requested the 'early' narrow track version, but when they arrived I found the wide track in the box. He tells me that definitely the arms are off of an '86, and the only way to be sure on the narrow arms is to get him the part number.

The numbers on the w i d e arms I have-
right- 951.330.514.04
left- 951.331.513.04

The brake rotors are approx. 12- 12 1/4" in dia. and 20mm thick.
The calipers are the single-piston floating type. The arms appear to be incompatible with my stock 1969 double layer spring plates and have no provision for a bump stop.

I could use some help in the form of part numbers from those of you with the narrower aluminum trailing arms, although I have to confess that part of me wants to just go 'turbo' and use the wider arms along with flared fenders and big tires.

Also find attached a modification of the arm compare photo.

- Mark. (Bugnutz) (1969 beetle, owned since 1976)

[Superman]

Guess I failed to mention in my original post about the bump stop. Perhaps Alex can post about the older cars with the double spring plate. Mine is a 73 and I went with the steel arms. Oh and welcome :D

[MattKab]

I got both the sexy '87 951 cast arms and the '86 944 steelies. I will get past the output flange issue so I got the early arms with hope of obtaining T181 O/F's or finding a Quaife in my cornflakes and The longer, more springy 951 axleshafts.

I learned they require use of the spring plate off the same car or some normalising (welding) of a spring (Plate). The springplate bolt holes on all (Porsche and VW) steel arms go like ,' , on the cast arms they go , ' , the corresponding springplate must be wider :confused: I believe the end of the '03 torsion housing needs modification to take the 951 springplate?

I cut a sourced spring plate for a mock-up, rather than machine the 951 (THIS IS NOT A VIABLE MODIFICATION AND IS AGAINST THE PHILOSOPHIES OF BOTH MYSELF AND TRUE GL!)

The rear track was increased and wider rear wings would have been necessary to clear my lovely 7.5*17/et52mm 225/45.

Please bear in mind my Beetle gets decomissioned Friday evenings and put back to stock by Monday morning for work. This goes on until developments are figured out for satisfactory execution. Only the fasteners and faces get detailed at the mo.

From memory (March '02) the bushes are a straight swap for the Bug ones and it bolts straight up. nice and light. The '03 single plate springplate is in the right location but only top 2 holes line up (LOOK 4" /\ ).

The shock absorber bolts on the 951 arms are M14 fine thread, a serious bolt requiring a simple lathe job to make a shouldered stud for the 12mm bottom damper eye.

When the shocker is bolted up at the bottom, I noticed that the top eye was off axis to the bolt hole in the '03 shocker mount by a degree or so? I checked my work and concluded the shocker on the 951 shocker travels about a different centre.

The top bolt will go in but I didn't like the feel of the loading in the top bush. It doesn't fit. Easy sorted with a new M14 thread in the shock tower and a 14mm ID bush in the top eye of a Bug shocker.

Does this line up when the 951 springplate is used?

Matt

[MattKab]

And the opposing static bump stops! Thanks Superman :)

[Superman]

Originally posted by MattKab
'87 951 cast arms and the '86 944 steelies

In the USA, it would be '86 cast and '85 steel. According to my parts source there were 4 arms...

==========
83-85 944
==========
86-89 944 S
==========
86-89 944 Turbo
89-91 944 S2
==========
89 944 Turbo S
90-91 944 Turbo
==========

Note: The 968 most likely has the 944 S2 arms and the 968 Turbo S has the 944 Turbo S arms.

[Superman]

Opps, let me add... if you want the cast arms then get the 86-89 944 S ones but again check the shape of the arm. Personally I went with Bug steel arms as the 944 arms don't offer that much more adjustability for the work involved to install them. Some may disagree but for what my car will be (summer weekend cruiser) it seemed too much.

[zen]

so for those running the wide arms, what are you doing for a bumpstop since the arm does not accomodate for one?

[SilverBullet]

Drilled and tapped and used a bolt (size) just nice to fit the bumpstop. :)

[zen]

i assume that is on the shock tower. where does it hit the arm? i don't see a place set for it.

[boygenius]

Please post a pic. :)

[boygenius]

Zen. do you remember how much space is between the bump stop and the shock tower on the stock suspension. :confused:

[zen]

LOL. no, another thing i was looking at at the same time as you. i sat there kicking myself for not taking measurements. ah ha, i took pics though. one is attached.

[boygenius]

If you mount the bump stop upside down so that it attaches to the shock tower you only have a 2" gap, that works out to 3-1/4" wheel travel. If you mount it to the arm on inside of the spring plates the gap is 3" and the wheel travel is 4" to 4-1/4". I guess the ultimate bump stop location will be decided by wheel travel. What is stock wheel travel???

[boygenius]

OK, the distance between the bump stop and the shock tower is approximately 4-3/4" with stock suspension. I will remove my bushings from the porsche arms and re-install them in the VW ones and take more acurate measurements. :)

[zen]

are you taking those measurements with the spring plate on the lower stop? just curious. also a shorter bump stop should work as long as it still have a safe buffering. not sure what that is, but remember reading this somewhere, so probably worth investigating.

[SilverBullet]

Drilled and tapped on the alu. trailing arm where there's a circular area! Pardon my discription! :) Only 15mm from bumpstop to body! Using 225/50/16 tyres with 15mm clearance from tyre to fender and shock solid hard! So far no cracks or tear on the bumpstops. :)

[boygenius]

SilverBullit you have the early arms, We with the late arms don't have the flat area on the trailing arm. Not going to be that easy for us. :(

Zen, I measured the stock suspension and there is 3-3/4" between the bump stop and the shock tower with the spring plate resting on its stop. That works out to 5" of wheel travel. Also the center of the stub axle is 1.5" higher on the 944 arms than on the VW arms, lowering your car an automatic 1.5". With the 944 suspension one of the places I'm thinking of placing the bs is upside down on a plate of steel between the rear body mount and just on top of the top of the bs plate on th eshock tower. Basicly look at your rear suspension and draw an imaginary line horizontaly from the rear body mount straight back. Then you could cut out the part of the stock arm that holds the bs and weld it to the steel so you could just use standard VW bump stops. Placed there you get 5" of wheel travel. :)

[zen]

since i ended up with both early and late ali arms, i thought i would share a pic showing track width differences. i did no measuring and these shots are hardly scientific, but the difference in width comes from the hub. there should be no difference in the length of axles required. spring plate mount is obviously in the same place as well.

here's what they look like (early on top, late on bottom)...
http://www.volksport.net/images/projpics/zenearlyvslatetrackcomparison.jpg

those come from a 924S/86 951 for the early and a 944S/late 951 for the late arm. also, here is a 86 951 rotor on the late arm. goes to show the difference (not i get to order rotors again)...
http://www.volksport.net/images/projpics/zen86951rotoronlatearm.jpg

[jhelgesen]

Hey Zen, I can take those rotors off your hands, I'll need a pair for the vert.

[zen]

i'll probably just hold onto them and use them on my 951. it is not too far off from a brake job. haven't measured the rotors on it though. i got these from Vertex for $65 each though. shipping is what kills the deal.

[jhelgesen]

i'll probably just hold onto them and use them on my 951. it is not too far off from a brake job. haven't measured the rotors on it though. i got these from Vertex for $65 each though. shipping is what kills the deal.

Oh yeah, forgot you had that water pumper. No prob.

[Tim]

Hello Zen,

As you've got both early and late alu arms side by side, does it look ok that the hub of the early alu arm can be used on the late alu arm?

Thanks
Tim

[barbe]

Hello! I have a 1303 or superbetel, of the 72. I need the back arms porsche 944, but which year? My car has the suspension top behind. I thank for all the help

[barbe]

i need two:
the first is 944 for the 89
and later is 944s for the 87

[boygenius]

The early aluminum arms are easier to use, year 1985.5 to 1986 because there is a place for the suspension bump stop.

The later trailing arms 1987 and later are a little wider so there is no need for wheel spacers when running most wide wheels. But there is no place for a bump stop to limit suspension travel. Hope that helped.

[barbe]

merci&thank's

[Bugnutz]

Zen,

Thanks a lot for sending the photos. I am working on exactly the same problem- I don't have enough fender clearance, and will need to change from the late "dished" hubs and wider hat section rotors to early flat hubs and the rotors like your new ones. The photos will help out a lot when I go for the parts.

Regards, Mark.

[zen]

Hello Zen,

As you've got both early and late alu arms side by side, does it look ok that the hub of the early alu arm can be used on the late alu arm?

Thanks
Tim

i've never had them apart so can't speak for bearing, stub and hub interchangeability. some others here might be able to. attached is a better pic of the hub comparison. not much of a help, but better than nothing. :)

[Tim]

Thanks Zen. The lock nuts look the same but not sure if the number of splines and the diameter of the stubs are the same.

Regards
Tim

[zen]

Thanks Zen. The lock nuts look the same but not sure if the number of splines and the diameter of the stubs are the same.

Regards
Tim

i will try to get some measurements on that, but am in a bit of a scramble. remind me in a couple weeks if i haven't done it. will try to do it in the next coupld of days though.

[LOAF]

Question to all,

Is it possible to limit the travel on the rear (regardless of whether it is an early or late alumn. set up by using a Macpherson Strut (Bump stop) Bushing. Like most new cars have on the front. But for our application install it on the rear strut?

If possible this would seem like a much easier solution than finding a place to install the vw stop..

Now that I have my assembly (late alumn) and am ready for the install, I am noticing more and more issues.. :bawling:

But that is life :)

ALex

[boygenius]

Bump stop pics...

I used some summit universal bump stops an ddrilled and tapped the shock tower at the correct angle so they would hit the top of the trailing arm. On the right side I screwed up the angle and broke off a tap in the shock tower. I wnet to home depot and bought a .06 cent nut and welded it into the shock tower at the correct angle... :)

[LOAF]

Sorta what I was thinking.. but your idea is better..

Thanks again.. and nice...
Alex

[boygenius]

Just a simple way to get your trailing arms pretty straight when bolting them up. I used a 3/8" drive extension and a 16mm craftsman socket to hold the trailing arm in place while the bolts were tightened down. At least that way your rear end would be straight enough to get to the alignment shop.

[Humble]

that's a pretty high tech alignment tool ;)

i just picked up a second set of trailing arms to do a straight up swap. they guy says they're off an 87 944 turbo. 4 pot calipers all around, but the rear arms are funky.

they have the early cast in bumpstop, but the late wider track. just when i though everything was making sense :P

[boygenius]

Hmmmm. Can you post some pics. I know that the 1986 turbo had the early aluminum trailing arms with less track increase.
Well since they have the bump stop area in the arm that should make for one less challenge in installing them. ;) :agree:

[Humble]

no prob, i'll have to get a camera from work so it won't be till mon or tues. basically it looks like the early alu. arm with a late turbo hub. i'll measure the caliper bolt spacing and see if there's a difference in the 2 sets of arms also

[boygenius]

Maybe someone switched rear hubs to get more track for their car. :confused:

[Supa Ninja]

I got the complete rear suspension from a '86 NA and I measures the track from the spring plate and it was the later style as well as it uses the longer half shafts. I wonder if they went to the wider setup mid 86?

[jonnyspatter]

Thought you might like this pic.
On the right is a standard 1303 seni-trailing arm, in the centre is a steel 944 arm (which I think is identical bar the wheel hub assembly), while on the left is an ally 944 arm.
I was going to use the ally job on my '03 until I saw the extra width it'll add to the rear wheels!
http://img.photobucket.com/albums/v511/jonnyspatter/DSCF0283.jpg~original
Another point to note is that the bolt pattern for the ally arm will not fit the 1303 spring plate, where the steel will.

Hope this helps. :)

[wrenchnride247]

I need the wide trailing arms for my bug. The wheels i've got are 993s the fronts are 7x16 with 55mm offset and 150mm backspacing, while the rears are 9x16 with 70mm offset with 190mm(wow!). I have 2 inch wider fenders front and rear, so i need to push the wheels out to the fender lips. Will the front hubs from'92-'95 968 add more track like the rear arms will?

[jmd]

a question about spring plates. Are there simple solutions stateside for this? I have spent 3 months looking for a set of spring plates, and it seems each Porsche dealer I speak to has a different Idea of what I am talking about?! So what I am trying to understand is, what spring plates do I need to get in order to continue the install? In a photo above there is a bright silver spring plate cover... what is this from? also is there a way to ditch my rear torsion bars, as I would like to use coil-overs but still require a springplate / uniball something or other... Anyone have insights for this?

Thank you.
(86 alloy arms on 69 IRS pan -body clearance a non-issue, just want the arms to function as installed.)

[Steve C]

Hi

This is an 944 adjusting tool a friend quickly made up on his lathe from some hex brass.

Steve

[C4 Metal Werks]

With the Early (top) will widen track by 43mm is it possible to use alloy wheels and stock rear fenders?



Okay here's the scoop on 944 aluminum rear trailing arms. First off, throw the part number, year, and model out the window. Every source says something different. It's very confusing and I've never figured out the "code" yet. The best thing to do is just look at the arm, there are two versions. In the pic attached the top version is "early" and the other is "late". These are terms I have used and may not apply. Anyhoot, just look for the arch as pointed to in the bottom arm and you'll know this is the wider of the two versions.

Early (top) will widen track by 43mm
Late (bottom) will widen track by 74mm

Credit: pics and info from the book Kafer Tuning by Helmut Horn

[zen]

I'm not 100% on this, but doubt it. If I'm not mistaken, wouldn't the 43mm push the wheel mounting surface out past the fender lip on its own? No wheel offset is going to make up for that. If you went to 1-1/4" wider fenders, then yes, with the right offset you are fine.

[C4 Metal Werks]

That was my thought as well. I will keep looking for a steel right rear control arm.

I'm not 100% on this, but doubt it. If I'm not mistaken, wouldn't the 43mm push the wheel mounting surface out past the fender lip on its own? No wheel offset is going to make up for that. If you went to 1-1/4" wider fenders, then yes, with the right offset you are fine.

[SilverBullet]

is this 43mm or 74mm per side or for both sides?

[Steve C]

Hi

I measured my 1303 bug which had Type 3 rear drums fitted, then with early alloy arms. I've been told that Type 3 rears give a very small track increase.

Rear track wheel bolt face to wheel bolt face
1303 with Type 3 drums 1405 mm
1303 with early 944 alloy arms 1490 mm

Steve

[evilC]

Our 1303 has 924S alloy arms with 7" teledials on the rear and with a 31mm spacer the wheel sits perfect with +4" wings (fenders)

Clive

[zen]

is this 43mm or 74mm per side or for both sides?

Per side. I have late arms with 951 brakes/rotors, 8.5"ET48 wheels and 3" fenders and the wheels nicely meet the fender lip.

[SilverBullet]

I just got the late trailing arms without the bump stops, but when I compared the early and late, it looks about the same! Could it be the rotors that widen the track? Or the early alu arms came with bumpstops and without.:confused:

[SilverBullet]

Without bump stops L side: 951 331 513. 8R
R side: 951 331 514. 8R

With bump stop R side: 951 331 514.1R , 951 331 514.0R
L side 951 331 513 1R

I have 1 extra right side with bump stop.
Could it be the hubs, rotors that increase each side by 31mm?

[1303GT]

just for some info,
86 and back 944/951 with non ABS used ET23 wheels, 87 and up ABS cars, the hubs changed to a wider track, and the cars went to et53 wheels, so yes the hubs are wider on the later cars.

John

[SilverBullet]

Thanks John for the info, will set it up soon and will post the difference.
Cheers.
Ric

[Tim]

I have late alu arms (no bump stops) with early 951 hubs and 7" cookie cutter (ET 23). The wheels just fit nicely in the fenders with 2.5" universal flares.

[Bug@5speed(US)]

TIm,

Which fender flares are those.. are they generic, or miata?

Let me know, I have been wanting to do the same, as a way to get around not buying flared fenders.. I thought no one had gone down that road yet..

Any info appreciated
Alex

[Tim]

TIm,

Which fender flares are those.. are they generic, or miata?

Let me know, I have been wanting to do the same, as a way to get around not buying flared fenders.. I thought no one had gone down that road yet..

Any info appreciated
Alex

Hi Alex, they are universal fender flares I bought on Ebay. I think the set I got was made for Datsun 240Z and it was shipped from Thailand. I think there are many vendors selling the same or similar things in the US too. Just search on Ebay "universal fender flares Datsun" or "240Z".

[Tim]

TIm,

Which fender flares are those.. are they generic, or miata?

Let me know, I have been wanting to do the same, as a way to get around not buying flared fenders.. I thought no one had gone down that road yet..

Any info appreciated
Alex

Hi Alex, they are universal fender flares I bought on Ebay. I think the set I got was made for Datsun 240Z and it was shipped from Thailand. I think there are many vendors selling the same or similar things in the US too. Just search on Ebay "universal fender flares Datsun" or "240Z".

[Bug@5speed(US)]

Tim,

Thanks, they look like they fit quite well the arches of the beetle.. are they fiberglass or plastic?

Thanks for the info..
Alex

[DORIGTT]

Hey,
Did anyone have trouble with the spring plates not sitting on the droop stop?

[Steve C]

did you give the chassis a clearance grind for the head of the adjusting bolt?

[DORIGTT]

Hey Steve,

I didn't.

Just that hole is enough to clearance the area?
Will I still be able to use the adjusters for alignment purposes?
Does this require a specific spring plate cover? I've got a 1970 with dual blades on the spring plate, and another person said I need to use the later versions without the spacers on the back so it will suck the Porsche springplate in tighter.

[Steve C]

The big nut will drag on the chassis if you dont grind some metal away

You can still get to the toe and camber adjusters, the big nut is hard to turn because the chassis blocks it, I found a thin (36mm I think) spanner on eBay for a clutch fan I think

I used cut down 944 alloy ones on my car with Beetle inner rubbers and 944 urethane outers

you see my 944 outer cover in this photo

[DORIGTT]

I take it that everything lines up properly and all works fine like that eh?

Would running non Porsche covers work?