Open Road

SeanR wrote: ↑Thu Aug 20, 2020 11:47 am BTW Dave, if you don't have one of these, find one. Makes life easier.

Sean, why don’t you start a thread on the impending ABS harness doom we all face and I’ll respond there. A bit awkward to find a pic for every post to keep a tech conversation going. I’d do it now, but I’ve got some stuff to for the next few hours.

ABS harness doom is something every 928 owner will face soon if not already. For pre'94 928s there are three distinct wheel well harnesses that deteriorate with age. Only a few are still available for certain model years.

For '94+ it's even worse because the wheel well harness are not separate from the ABS body harness. It's just one big harness that runs all over the GTS.

I'll post more later and answer @SeanR 's questions from the picture thread.

LOL, I was in the middle of typing up this exact thread. Well done man.

So my left rear harness found itself laying on a highway somewhere, destroying everything around it. Barrel connector gone, and all the wires ripped out of the car all the way up to the grommet going in to the battery box area. Fun times.



So in trying to source a new/used one, not many seem to be available. Roger says nothing new from Porsche. Mark A @ 928 International says he may have a couple of new ones in old stock, and if he does I'll pick those up and take what I have and dissect them and see exactly how Porsche had them made and then replicate them using weather packs or Deutch connectors.

I was almost to the point of taking my good shape new ones, installing them in my car, then tearing the old ones up to see if I can make a rear using those bits, to keep it somewhat stock.



Roger also thinks he has some trashed ones on a burnt '87 he has in his lot and will go over in the morning and see what he's got and can go forward from there. I know I can make new ones using new stuff. Will update more as things go forward.

Hello Sean, could you re-post your images above? No joy. Thanks. Dan

Daniel5691 wrote: ↑Thu Aug 20, 2020 5:27 pm Hello Sean, could you re-post your images above? No joy. Thanks. Dan

They are showing for me......Worf? Can you see them? I used the same posting technique I've been using.

I can see them......I lurk here too. :mrgreen:

Yeah. I see 'em.

First, Sean lemme answer your question from the Picture Thread. Yes, my barrel grommets come from the same dude. However, I've got a FISA letter telling me I can't described the mechanism through which they get to me...

One thing... those grommets come in two sizes. One size for me and a different size for everybody else.

The first time I got a set of these I noticed that the hole in the middle was sized for 'pre-89 harnesses and was too small for '89+ so, after much grumbling, hand waving, accusations that I didn't know my ass from a hole in the wall, I now get versions that have a larger (by <1mm) hole that fit well with the slightly larger harness covering on the '89+.

More on the differences later for those that don't routinely see a variety of 928 pass through their hands.

SeanR wrote: ↑Thu Aug 20, 2020 1:55 pm So in trying to source a new/used one, not many seem to be available. Roger says nothing new from Porsche.

There is a smattering of them. A while ago I went the the various permutations and figured out which ones you could swap year to year. IIRC the ones with provision for RDK are backward compatible with pre-RDK, but IIRC the only ones available were pre-RDK NOS. And not a complete set. Like only the front-left or something like that.

SeanR wrote: ↑Thu Aug 20, 2020 1:55 pm I have and dissect them and see exactly how Porsche had them made and then replicate them using weather packs or Deutch connectors.

The problem with that, of course, is that you have to cut the body ABS harness and then if you ever replace brake pad, ABS, or RDK sensors you have to mod the new ones with the connector. And you have to come up with a new retainer on the hubs for the new connector body. I for one am not excited about all that.

Also, I know that the pre-'89 harnesses had no shielding. I *think* the '89+ harness have shielding for the ABS and RDK. But, I won't bet even a duplicated body part on that. So far the harness covering only degrades on pre'-89. The '89+ harnesses are all still in good shape but the rubber grommets are all shot (or will be very soon) on both versions.

Both versions can get circuit breaks inside the connectors or where the harness enters the connector.

My eyes tell me that the white (now yellow with age) barrel connector bodies are molded around the three individual pairs of circuit connections thus making it more-or-less impossible to 'splice' in a good barrel connector body on to a good harness with visually acceptable results.

The dude that makes the rubbers has made molds for the barrel connectors. As of about 2-3 years ago he was not offering all components necessary to do a DIY harness build.

Last, God help us when the '94-95s start coming down with ABS/BPW/RDK errors that are traced to the wheel wells.

certainly not to hijack the thread... but all I'm seeing is this ....
All other images in thread are visible. Thanks gentlemen. Dan

Daniel5691 wrote: ↑Thu Aug 20, 2020 7:49 pm certainly not to hijack the thread... but all I'm seeing is this ....

All other images in thread are visible. Thanks gentlemen. Dan

Sean's images are hosted off-site and referenced via HTTPS. Mine are uploaded and hosted on-server here.

So, I would suggest that you bring this to El Jefe's attention here:

https://openroad.site/viewtopic.php?f=11&t=363

referencing this thread. If I had to guess, I would guess that your browser is blocking cross-site HTTP requests or that the domain on which Sean's pictures are hosted is inaccessible to you. A trace route to "scontent-dfw5-2.xx.fbcdn.net" might be helpful as would be the knowledge that that's a Facebook-owned domain. Perhaps you have blocked Facebook on your end?

Sean, if you succede in building and offering a harness of comprable quality, I'm in for a couple sets as backups for my aging GTs...

Is the ABS circuit the same one that brings in the "Brake Pad Service light"?
I didn't have that light before, replaced brakes and sensors at all 4 corners
and now I have the light.

Duh!

hessank wrote: ↑Tue Aug 25, 2020 10:37 am Is the ABS circuit the same one that brings in the "Brake Pad Service light"?

Yes and no. They are separate electrical circuits but those circuits are in the same harnesses. So, harness deterioration can effect both ABS, Brake Pad Warning (BPW) and RDK (if so equipped.)

Received my NOS 89+ harness from Mark, and it's not NOS. It's in a baggy with tags but the barrel is dirty, crust on the grommet and the insulation is cracking off the entire thing. Already shot him an e-mail about it.

worf wrote: ↑Tue Aug 25, 2020 12:27 pm

hessank wrote: ↑Tue Aug 25, 2020 10:37 am Is the ABS circuit the same one that brings in the "Brake Pad Service light"?

Yes and no. They are separate electrical circuits but those circuits are in the same harnesses. So, harness deterioration can effect both ABS, Brake Pad Warning (BPW) and RDK (if so equipped.)

Thanks Worf.

SeanR wrote: ↑Tue Aug 25, 2020 12:35 pm Received my NOS 89+ harness from Mark, and it's not NOS. It's in a baggy with tags but the barrel is dirty, crust on the grommet and the insulation is cracking off the entire thing. Already shot him an e-mail about it.

I've gotten sealed Porsche-labeled bags with rusty parts inside them. On the other hand, picking error is more likely in your case.

hessank wrote: ↑Tue Aug 25, 2020 10:37 am I didn't have that light before, replaced brakes and sensors at all 4 corners
and now I have the light.

The BPW circuit leaves the ABS harness and finds it's way to the central electrical panel. You can isolate from which 'corner' of the car the warning originates at the CE panel. Or, at least you can isolate front-left, front-right, rear.

That is true for pre-'90 IIRC. I don't recall if 90+ is the same off-hand. But the diagrams are pretty easy to figure that out.

I read somewhere before that the 89s circuitry was unique only to the 89s.

hessank wrote: ↑Tue Aug 25, 2020 5:16 pm I read somewhere before that the 89s circuitry was unique only to the 89s.

It has unique elements at the detail level, but the circuit design is consistent.

No model year in you signature. You have ‘89?

Profile updated.
Yes, 89