Porsche 944 Brake conversion on 1303

[Bob Brugge]

Nice drawings! Did you use Inventor for those?
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Keep on Dubbin'!

[Dodgy]

No, Solidworks... I use it at work, so the handbrake cables were a lunchtime project!
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'75 1303 (current project) owned since 1989!
'72 Squareback - full resto completed 2008 - now sold
356 Speedster kit, completed 2005 - now sold

[$aint]

@Dodgy, thanks for sharing this! Especially the CAD models are very nice. Great to see a direct comparison between the different uprights.

Would you be willing to share the CAD models? I'm working on a wiki like project that will contain all kinds of info regarding 1303's, 924s, 944s and their interchangeable parts. I've only just started, but would really like to include CAD models of all parts if possible.
See http://rennsportengineering.com/wiki/ for the site and https://github.com/rennsportengineering/wiki for the sources.

I have a pair of 944 M030 uprights that I want to digitize as well. Did you just use calipers to measure yours or something else?

And did you use something like this to press the origin ball-joint out and the new one in? http://www.ebay.nl/itm/10pc-Ball-Joint-Press-Servi...SwA3dYTUMR
Or do you need a bigger set like http://www.ebay.nl/itm/21pc-Universal-Ball-Joint-R...SwVL1WCK0T ?

[H2OSB]

Revisiting what has become an old thread.

If I didn't state this before, I had coil overs on my 1303 I had built back in 2001 or 2002 that were made from VW Rabbit GTi struts (Mk1Golf to those of you from across the pond). Upon those struts I had wanted to use 944 spindles, however, in spite of having extra eccentric inner control arm bolts and two "crash" bolts per side I was always unable to resolve the common camber issue associated with using 944 spindles on a 1303, thus I had decided to go back to using 1303 spindles.

Work has finally begun in ernest on my 1303 and I decided I wanted to redo my coil overs because the Golf strut based coil overs made my ride height too low (The highest I could have my suspension was a 2.5 inch drop...i want more flexibility). In deassembling my suspension i discovered the flanges of my top crash bolts on each side were forcing the bolts to center in the slotted top hole, thus losing the camber i thought i was gaining by using crash bolts in the first place. The solution...i bought a set of Whiteline camber adjusting bolts. Suddenly, i now have all of the camber adjustability I'd always hoped for.

Oh, my new coil overs will be made from Porsche 944 struts, which are nearly identical to the previous struts except 1.25 inches taller. The camber adjusting bolts have a 12mm shank with a 14mm eccentric section which is what give the adjustability. Because of this, I'm back to using 944 spindles, and indeed, 944 brakes.

On the rear, I've always had a straight swap to 944, using swans and tubes purchased from VDub Engineering. The front has been the big mystery. The 944 uses a single piston sliding caliper, and I've always been concerned the front brakes would be too powerful and lock up right away. However, after discussing the set up with Lanner of VDub Engineering, I've decided to have a go using the stock 19mm MC with a 2psi residual pressure valve on the front. If I'm not happy with the feel, I've read a great option on a beetle with 944 brakes is the MC from a Volvo 240. We'll see.

H2OSB

[H2OSB]

I love the mods done to the spindle to correct the geometry for a 1303. My problem has always been lack of ability to do this work myself. I went to every local machinist and none would touch it. I even talked to swell known guy down in So. Cal who had an article written about him in HotVWs for modding 944 brakes to fit on a bus and HE was not interested

That said, I'm a bit confused about the spindles Dodgy used. They appear to not have the holes line up vs the 1303 spindle. Is this due to the spindles being sourced from a 944T? OR is it just a trick of the images? My 944 spindle holes line up perfectly with the 1303 spindle holes (I'm referring to the holes that mount the spindle to the strut).

With regard to 924 spindles, they had much promise, but came up short. They use the same bearings and arrangement as Beetle/914, thus could be used in a beetle application. They also use the 15mm ball joint. That's where the similarities end. The steering arm is identical to a 944, so the ball joint direction needs to be addressed. The biggest hurdle, however, is the spindle ears themselves. The rotors for a 924 are MUCH smaller in diameter than a beetle/ghia (278mm) or a 914 (281mm) at 257mm so are too close to the axle centerline. Lanner Khan and I tried to work out an adapter to use the spindles with 914 rotors but there simply isn't the room available unless the adapter is very elaborate. The answer would would be to cut off the ears and relocate them. Btw, the 924 ears have a 94mm bolt spacing which is the same as 944 rears or, better yet, the light weight 2 pot rear calipers with 44mm pistons from the early 80s Porsche 964. Those would be a great set of front calipers on a 1303. CSP sells a close to perfect rotor for that arrangement and I MAY continue to work on that for my future brakes.

For the immediate future, however, 944 brakes

H2OSB

[Dodgy]

Yes I think I have late 944T spindles, hence the hole pitch is different to early 924/944 & Beetles

I found a specialist welding company locally who filled the upper hole in the spindle (using correct filler and heating the part first) then a machinist mate at work drilled the new hole in correct location accurately using a mill.

Not much progress on this project as my garage has been demolished for house remodel. Hopefully back on it in a few months time...
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'75 1303 (current project) owned since 1989!
'72 Squareback - full resto completed 2008 - now sold
356 Speedster kit, completed 2005 - now sold

[Daddy o's 67]

I'm looking doing the Porsche brake swap to my 79 Super Beetle using 83-84 944 parts. The question I have is, from the balljoint centerline to the face of the rotor on a 944 the same width as the balljoint centerline to drum face on the SB?

Just trying to find out when changing to 944 parts how much wider will it or won't it be for wheel spacing.

[Dodgy]

944 steering arm is straight, while Beetle arm is bent inboard. So tie rods need to be longer by 30 mm or so. Kerscher etc sell longer rods off-the-shelf for these conversions, or if you are brave you can cut & shut your VW rods...
You also need to drill out holes in steering arm and press fit bushes to flip the ball joints over. (Same custom part as Standard Beetles)
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'75 1303 (current project) owned since 1989!
'72 Squareback - full resto completed 2008 - now sold
356 Speedster kit, completed 2005 - now sold

[H2OSB]

I'm using the tie rods from a rack & pinion super beetle for my 944 spindle conversion (I have a '74 with steering box). They work fine. Don't try just using the stock tie rods screwed out. Not enough threads to be safe.

H2OSB

[Daddy o's 67]

Thanks Dodgy and H20SB for the info. From what I've read I won't be able to flip the tie rods because of the rack & pinion steering on a 1979 model because of tie rod to body interference.

[Dodgy]

You should be fine, I don't think convertible has any additional reinforcement around that area different to my 75 sedan that will cause any interference issues.
With the wheels off the ground (full suspension droop) the tie rod MAY contact the bottom of the strut on full lock. I haven't checked if this is an issue with car on the ground yet. Max lock can be reduced slightly by adding spacers behind the bump stops inside the rack if necessary.
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'75 1303 (current project) owned since 1989!
'72 Squareback - full resto completed 2008 - now sold
356 Speedster kit, completed 2005 - now sold

[Karloz]

Great info, been looking around but this is the best. Doing same mod to my 73 3 bolt pattern. Got rear suspension from a 924T but didn't bring the front suspension and car got shredded. Later got a front susp from a 944 vert. No idea but from sticker on strut it seems to be from a 944S. Also brought along the 4 pot calipers which are very eyecatching with Porsche written on them. To fit the calipers to the rear 924 disk, I had to use spacers to center it. Originally planned on using cookie cutters but with the big calipers I had to go bigger and opted for 16" boxter rims. This setup fits lekker under the rear mudguard.
I had read that the rear was a straight swap, but the Kombi (T2) CV joints one uses, one has to have them machined to fit. Rear was fairly easy but the front is a headache.
Front strut springs are narrower so you can't swap them with the beetles. The Porsche front setup mounted on the bug (strut top mount straight swap), the car has camber issues and the front is as hard as a rock. To try and correct the camber I bought adjusters from Silver Project from Poland

but this only corrected about half of the camber. Going to follow your footsteps and giving up on the porsche strut setup. My stubaxle has no speedo cable hole, I presume yours doesn't either, How did you solve this? I want to retain the original speedo cable setup.

[Daddy o's 67]

The earlier 944's, 83-84 years, have the hole in the spindle for the speedo cable.

The stock 944 front strut springs are way to heavy for a beetle. Remember, 944 is front engine and needs the extra spring weight to support the weight. I'm planning on going with 2 1/2" diameter and 150# springs and modifying the stock 944 struts for these springs.

[tzepesh]

How did you solve the issue with the height adjustment bolts hitting the shock tower? As I recall, there is a 3mm interference.
I can think about either grinding the shock tower (which will weaken it) or add some spacers between the spring plates and inner bushing (which might lead to a wrong angle between spring plates and alu arms).
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'74 1303S, L98B Viperngrun (extra glitter), German Look
'64 1200, Sea Blue, under restoration

[tzepesh]

And another question, at what angle did you set the preload to the blades using the Porsche torsion bars? I guess it should be at a lower angle than with stock bars, otherwise the back would be sky high.
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'74 1303S, L98B Viperngrun (extra glitter), German Look
'64 1200, Sea Blue, under restoration

[DORIGTT]

Will Volkswagen single blade spring plates fit / bolt up to the Porsche 944T arms?
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To err is human, but if the eraser wears out before the pencil does you're a major screw-up.

[tzepesh]

No. Actually none of the VW blades can be mated to 944t aluminum arms. The aluminum arms must come with their own blades (plus they have some more adjustments!). Only the steel arms (924 an 944) can be mated to stock IRS blades.
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'74 1303S, L98B Viperngrun (extra glitter), German Look
'64 1200, Sea Blue, under restoration

[Dodgy]

Has been a long time since I posted here! There have been delays on this project due to work remodelling my house and building a new garage but I am back and making progress again! See separate thread '75 UK 1303 Build Thread

So I am now working at the rear end of the floorpan. The diagonal arms are sorted, although I am now going for a slightly earlier version of the Porsche arms that include a pad for the bump stop.
Looking at fitting the rear anti-roll bar from the 944, it quickly became obvious the fit would be very different than on the donor car.

On the 944, the roll bar fits closely under and slightly to the rear of the torsion tube:

However, on the Beetle, it cannot fit here because of the frame horns either side of the gearbox, plus the gearbox front mount:
(Note floorpan is inverted here, ARB is forward of the tube not connected to the trailing arms)

The Porsche ARB bracket was welded to the torsion tube at the end of each of the 'legs' plus the edges of the plate where the rubber fits to make a strong fixation.
So clearly the mount would need to be redesigned to position this further from the tube, here is what I have come up with:

This mounts the ARB directly below the torsion tube, with sufficient clearance to the frame horns and gearbox mount.
But moving the ARB forwards creates another problem - the 'arms' at each end are now too short to reach the link to the trailing arms.
I solved this by extending the arms by 60mm, welding onto this flat part is quite straightforward (lots of prep & heat to get good weld).

With this mod it all fits together quite nicely

By extending these arms, the ARB stiffness is effectively reduced. This is not a big issue as it is often reported that making the rear Beetle suspension too much can make it a bit tail-happy. So hopefully a good compromise.

So that is almost it for fitment of the 944 parts now.
Steering arms still need to be lengthened, but will have to wait for the body to be refitted for that
Next big challenge is plumbing & wiring the ABS module - yikes!
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'75 1303 (current project) owned since 1989!
'72 Squareback - full resto completed 2008 - now sold
356 Speedster kit, completed 2005 - now sold

[67rustavenger]

[H2OSB]

Hey Dodgy! Glad to see you back at it.

I have the 944 rear sway bar on my 1303. I followed the path of this guy https://www.gerrelt.nl/section-modifications/modifications-rear-swaybar

Looking forward to seeing what you end up with.

P.S. The pictures in my above link are not working. I used U bolts to hold my sway bar bushings/brackets. To choose the length of the brackets, I attached the ends of the arms to the trailing arms then swung the sway bar up high enough to clear the frame horns with about 18mm(approximate) to spare. I had no fitment issues. I don't feel the brackets are too low at all. If you look through the Kerscher site, you'll find they offer their rear brackets as a stand alone kit. I made mine similar to that design, however not as long(low, deep, etc). https://www.kerscher-tuning.de/kaefer/index.php?gruppe1=Fahrwerksteile&gruppe2=Stabilisatoren

H2OSB
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(o\_i_/o) I'm not a vegetarian because I love animals, I'm a vegetarian because I hate plants.