Porsche brake conversion Pt3

I think I've been a bit sidetracked sorting out the brake conversion instead of getting all the welding completed, probably because it's more fun seeing shiny bits coming together.

The problem with the rear disc diameter being too small was solved with replacing the 944 >88 discs (289mm diameter) with 944t (928s2/928s4) 299mm diameter ones, these new rear discs are a little thicker at 22mm making it a squeeze fitting the caliper when they have new pads. The new disc cost an extra £30 a pair; this reminds me why I have a Vdub and not a Porsche.

The caliper is a pretty tight fit in the back off the 15" wheels; there is a slight rub on the wheels' inner shoulder where it rubs on the front caliper face so I'll need a wheel spacer of about 6mm to get the minimal clearance all around. It's not what I wanted to do. But it's something I'll have to live with.

Trying to find 14mm washers in the local DIY shops to use as wheel bolt spacers was harder than expected so I've resorted to using 15mm plastic water pipe. I first cut them 7mm thick that didn't work, then at 9mm and this still rubbed in a few places on the inner wheel, This meant pushing the wheels this far from the hub gives me the next problem of having to use longer wheel bolts, so I may just space the wheels enough to get to get 4mm spacing from the caliper keeping enough thread for the wheel bolts and clear the small amount of material from the caliper to clear the foul.

I popped down to a local Porsche show room in my bug to collect some caliper mounting bolts, after a scan of the 911,s I was greeted by a pretty lady behind a desk asking if I would like any help, explaining why I was there and a phone call later a suited gentlemen arrived with my £6 bag of bolts, a little surprised I paied and started to ask about caliper piston sizes and brake master cylinders, "sorry I don't study the breaks" silenced I decided it was time to leave. You can't beat speaking to a grubby mechanic who knows there way around the cars they work on.

With new bolts I mounted the front caliper to the wooden bracket I'd made and with the bearing spacers fitted I was able to work out that I needed 11mm offset to centralise the caliper on the disc. I'll now have this bracket machined once I decided the best place to position the caliper around the spindle. Although I'm still unsure if I should use my link pin or ball joint spindles and beam.

Porsche brake conversion Pt2

After all the previous measuring I realised that using only one spacer behind the inner bearing to take up the 8.5 mm lateral play would push this bearing off the flat running surface and over the tapered portion of the spindle, so I decided to (ask my kind, old school engineering uncle with cool 40 year old tools, at the cost of a portion of fish and chips to) turn down the inner spacer 6.5mm thick with a taper to allow for the spindles' inner radius. This slid on with a slight tap and allowed the inner bearing seal to sit on the original face and gave me a gap of 9mm behind the disc to fit onto the original wheel cylinder mounting holes a mounting plate for the calliper.

The vision of a shiney Fusch wheels and polished callipers isn’t as easy to pull off as “oh you need some 944 hubs to do that” Its hard to get the right parts when you don’t know the model and year of the car, you cant just ask for a rear disc with about this much diameter and the depth to fit the rusty hub you plonk on the counter, But the bloke at the parts shop was intrigued with what I was trying to do and was very helpful pulling parts off the shelf’s till I found what I thought would fit.

I like (more stare at each time I see one) the 996 / Boxster style of Porsche mono block (all once piece) callipers but these are for 320ish mm diameter discs to fit 16”+ wheels and would be to much trouble to fit in my 15”ers So the power of eBay drew me into it's grasp for a month while I tried to obtain a set of 944/924 Brembo callipers for a fair price (Inc postage). Of course the description is not always accurate. What I received needed a full check up. this included freeing a couple of pistons new dust seals and some corrosion treatment.

During my clean up and inspection it became apparent I'll have to sort a few things out. There was corrosion around one off the pistons holes that will need blasting to remove it and that piston was seized, this was because of corrosion on the surface. I found out after I levered it out that there’s a removal tool that probably makes the job a lot easier. Also the piston sizes weren’t matching and the rotation arrow was the same. Each calliper is manufactured with two different size pistons, the smaller of the two at the leading edge. I ended up with a pair of 36mm-40mm that Ill use for the front but have a right hand 32mm-36mm and a right hand 30mm-34mm. This is the problem of doing things on a budget, you get what you pay for. I'll look for something better later but for now they will help me get everything fitted OK.

Fitting the calipers’ to the rear 924 swing arms should be a bit easier than messing around with bearing spacers. With new discs trialed on and the calipers pads centered on these, I’m able to work out the spacing between the original caliper attaching threads on the rear swing arms and the calipers. If I sit the caliper so the pads are on the center of the disc it foul's the disc on the lower part of the caliper, and because the rear hubs came with out rotor attaching parts (two counter sunk disc fixing screws) Ill need to sources these to get the disc fixed securely so that the measurements I need to adjust the caliper are correct.

If I fit the caliper to the original mounting threads on the rear swing arm the pads over lap the disc. The easiest way to solve this is hope there a wider disc with the same offset for the hand brake drum assembly. I think the Brembro calipers are fitted to turbo 944 so that could be an option, although that may mean a bigger disc off set for larger turbo style wheels. I'll have to have a chat with the parts shop again and see if they have any thing that will help.

Grabbing a few spare bit of pallet wood I knocked up a front caliper mounting bracket this gives me a visual idea of the calculations and drawings I've been spreading around the garage on each piece of scrap paper I could find, With a bit of fine tuning. I'd like to get this part CNC (Computer Numerical Control) machined at a local shop, but if its to expensive Ill make it from plate steel and weld on and tap the spacers/ mounting holes. All of this and I still need to work out how to pressurise this lot? I'm sure the original single circuit master cylinder wont be up for it!

Front Valance Pt3

Well back to the job of repairing the front valance again. I’ve been going back and forth to this job for too long now and I decided to post the work once compleated..... ish. With the joining brackets fabricated I set up my new 160 amp welder to fit these on. Wow how much easier it is to weld with decent kit (although I’m still not perfect), the small old hobby welder I’ve been suffering with will defiantly get the boot. The bracket was tacked on with ease and the lower flange I decided to bend to the profile of the closure panel when its trial fitted.

I drilled and tacked some nuts inside the valance for attaching the cab floor belly panel because unfortunately this panel didn’t have the forming for these, I then trialled the valance front closure panel using the lines drawn on tape Id marked as a datum long; long ago. With a bit of forming at the ends and re-measuring, the panel went on with no problem. I tacked the lower part from the inside the valance and discovered the joys of welding upside down. The welding burns are a lesson learnt, and it could get hot and sweaty stuck in a garage with all that protective gear now the summers coming.

I received the new lower front panel (which I specially requested without the cut out for the nose and longer at the ends so I can fold it over like the original.) Rather than butt weld this panel I joggled a small lip on the repair panel to sit inside the original one. I ground a ton of filler off the front panel so I could ensure the repair panel was straight, although a bit tricky around the nose; using some fabricating magnets and clamps the panel fitted OK.

Eager to get the panel on I started tacking it together, then double checking the fit before I went welding crazy I noticed that the joggle at the left corner end of the panel was overlapping to much, and causing the curve of the panels not to sit flush. Access to the back of this panel is very awkward because of the front light bowl and inner kick panel, this ruled out any fabrication from the back. So I painstakingly cut the joggle off from the front with a cut down junior hacksaw clamped in a pair of pliers. This did the job of letting the pannels sit flush, and then with the magnets in place I continued to tack it all together.

Learning from my cock up with warping the dog leg panel I spaced out the weld points and spot welded the a seam between the two panels with only a second spent on each weld, but still the original part of the panel had a slight ripple along its curve. Not sure if I’m being to particular about my work or still have a lot to learn but I'm determined to get it right. So I guess Ill rely on the paint prep to get rid of any imperfections (filler).

I cleaned up the welds and with a few tacks along the lower lip and tidying up the wrap around part of the edges this job is finally finished.