gasmanstl

Yikes. I have now seen the gates of hell...my CE block (85 euro) is sitting on my dining room table. Inspired by the tale about repairing electrical gremlins, brighter lights, voltmeters actually reading the right numbers, etc. posted by Sharkskin on his very useful website, I have begun the electrical rehabbing of my shark by attacking this spot, where more connections live more densely packed than anywhere else...seemed logical to me. Gawd, am I glad the whole thing didn't sproing apart with watchsprings and Jesus-clips when I took it out I have some questions and comments. It is already pretty clear to me that this was a smart thing to do, as all of the fuses were seriously corroded, and their receptacles are likewise as corroded also. Relays are all out, and most of them were pretty badly corroded too.

I have noticed that some of these fuses (which are attached to circuits which were known to be functioning) - appear on the backside of the CE to be attached to *nothing* on one pole of the fuse! Some grey wire is attached to one pole, usually the bottom...but NOTHING appears to be attached to the upper pole! How is this possible? I had an aftermarket stereo put in last year, and the shop dude stuck a connector blade into one pole of an unused fuse to draw power...and it *works* ...but when viewing the backside of the CE, there appears to be nothing but an empty prong.

Where the CE panel screws in, at the top, just by those screwholes, one on each side, there are two in-line fuse holders attached to wires that are clearly part of the native harness, about 18-20 gauge or so, clipped into metallic clips. I presume they're both the same, but I only took the right-hand one apart; it contains a small tubular fuse of 4A value, which appears to be a slow-blow. What are these fuses for?

The first thing I started doing is cleaning the fuse receptacle contacts. Lots of gunk is coming out out of these, so I'm glad I'm here. I queried my mind for awhile as to the smallest (thinnest) file I could think of to do this - and a metallic nailfile of the type used by female-persons to dress up their fingernails was actually thinner than the thinnest needle-file that I had - so I purchased a couple of them and ground one down to fuse-blade size and cleaned about 15 of them before it occurred to me to CHECK the tightness of the fuses after I was done. They're kinda loose. By shark standards, at least. Really, they're closer to what you see in most other cars with blade-type fuses, but still a tad looser. I'm curious if you all have used another type of device to clean these, and the relay receptacles, also. How easy is it to tighten them back up? I hope I have not destroyed these receptacles...but do they really need to be that tight anyway?? They're definitely the tightest fuses I've ever seen. If they can't be retightened, and really need to be that tight, I guess I could tin the fuseblades with solder before installing...

And on the subject of the *backside* of this thing. OMFG. I have only very rarely seen such a nightmarish thing. It was initially my plan to *remove* as many of the connectors as I could, and clean them, and reconnect them all after applying this contact enhancing/corrosion inhibiting product called "Stabilant-22," which comes highly recommended. Of course, nothing is marked or color-coded in any way, and most or many of these connectors are completely unaccessible under the maze of grey spaghetti covering them. Even if I were inclined to somehow attempt to disassemble this thing in stages and access these connectors, they're *horribly* tight. I removed one just for fun, and using a needle-nosed pliers, it was hard, and I was *seriously* afraid I'd break it getting it back on. I'm wondering if anybody has any thoughts or experience here. There is another product that some people have raved to me about, called "Deoxit," which I understand is more amenable to being applied to "dirty" contacts without physically cleaning them first. I'm kinda hoping Sharkskin will pipe in here...having lurked on this subject for a couple of days and read a good number of old posts, he's obviously very knowledgable in electrical areas.

Ah well, off to bed with me to get up at 0430...

Clay.

Alan

My advice - only dissassemble what you have to... real risk of damage to the panel & wiring. These connectors were not really designed for removal.

If you have water or heat damage - repair (disassembly/mechanical cleaning/replace if needed) - otherwise chemically clean the mated connectors and spray with an inhibitor if you must (designed to stop oxidation). The later panels are apparently tougher to dissassemble.

I would NOT dissassemble mine (I'd do most other things...)...

As Ed would say...YMMV...

BTW You can buy custom built contact files - very thin and double sided with very fine abrasive... Frys electronics has them for one. They are no thicker than a fuse blade - various sizes avail. more like feeler gauges.

Alan

SharkSkin

When cleaning the contacts you want to just remove the minimum material needed to get the relatively small surface areas brightened up.

If the fuses are not tight enough, you can bend the fuse blades slightly, maybe 5° each to help bind it to the terminals. kind of like below:

The downside of tinning the fuse blades is it may spread the terminal further, creating a potential problem some ways down the road.

As for the phantom fuse connectors, I think the later fuse blocks have a single internal "bus bar" that feeds all of the fuses in a group. I should really try to get my hands on a fubar'ed later panel so I can explore the details of how to disassemble/clean the later style fuse blocks and do a writeup.

The later style relay terminals have a metal tab that must be released from the front and two plastic tabs that must be released on the back to free each terminal. When Ron & I did his panel, we didn't disassemble all of these -- we replaced one slightly crisped relay socket and the rest we cleaned with a small file.

One thing about contact cleaners, some of them can be corrosive if left in place a long time. Combine that with the fact that any liquid you use on there will get wicked up into the wires. Be very careful, know what you're getting into. Stabilant wicked up the wires can only benefit you. A compatible liquid you could use to flush gunk out while cleaning would be isopropyl alcohol. Get the 90% stuff, most places sell 70%. I think I had to go to Drug Barn, grocery stores rarely have it. With some of that, a squeeze bottle like this one would be a big asset(pic attached for reference after auction ends). Use that with some acid brushes to get things clean, then leave the panel face-down in the sun or a very warm place for a day.

WallyP

The two small in-line fuses are for the door locks.

Stabilant will wick into the connections without disassembly - wiggling them will help a bit.

Corrosion Block is another good product for this.

gasmanstl

Thanks, gentlemen, for your help...will advise of developments if relevant...hopefully not to say"it won't start" or "I smell smoke..."

gasmanstl

Further developments...have checked all of the orig 17 fuseholders I did by wirebrushing fuseblades and checking for marks when I inserted them...all fine (seems that more of that surface area should be being used, though...but the ones I did were about as good as the ones I did not as far as fuseblade marks are concerned.

Fuse blades are .026 ...nailfile was .030. I did get a "real" electrical contact file from a local electronics shop (thx for tip) and it was only .011 - too thin to really use, so I folded it double in a vise and it was .028 - I decided to use it because the grit was more appropriate, IMHO. It was absolutely perfect for the (female) relay connectors, too - width, I mean.

So on to the Stabilant. I have disassembled a number of the relays, and found corrosion and pitted contacts on them as well - cleaned them up with emory paper. Question: I wonder if you all would use the Stabilant on the relay contacts as well? Sounds like a logical idea...

Clay

Alan

Absolutely - sounds like its going well - good job!

Alan

SharkSkin

Actually, Stabilant is not suitable for relay contacts that switch inductive loads. In a number of their app notes they specifically recommend against using in contacts that may experience arcing: http://www.stabilant.com/appnt31h.htm

Alan

Humm,
Good catch Dave - I actually initially read that as relay terminals (as in the base terminals) I do still recommend it there. I think most cleaner/stabilizer products provide disclaimers on contact arcing - in which case you are back to cleaners only (e.g. low residue) in which case some kind of alcohol is certainly simplest (say just strong isopropyl alcohol for cleaning & degreasing) or use a switch cleaner type - switch cleaners do have the advantage of aerosol spray application - useful in this case - check their application notes. Best bet is to ensure the contacts are as smooth as possible to reduce arcing & rapid deterioration - finish them with the finest wet & dry you can find - then burnish with smooth card/ribbon - then clean chemically. I have used IPA on a plain satin ribbon material (my wife sourced it...!) smoothing & cleaning in one step...

When done dry fully with a hairdryer before putting the can back on - you don't want any vapors trapped in there.

Alan

SharkSkin

Also, I should have mentioned, most internal switching contacts in relays have a thin, hard plating on them, usually tin. If you have base metal showing on the contacts -- often brass or bronze -- then consider replacing the relays that were corroded or pitted. Often relays reconditioned this way will last a fraction as long as fresh ones.

Good advice on cleaning Alan -- best use for biz cards IMHO. BTW, I trie sourcing same way as you and have 3-4 bottles of 70% to show for it.

Mrmerlin

Hi, since your in there I would close the wood cover and look up on top of the fuse panel, look for signs of water leaking coming from the blower box there is a good chance that if the fuse panel has corrosion then the water is dripping onto your panel from the bottom of the blower box , it is the plastic grating that sits just above the fuse panel, the best thing to do is remove the blower motor from under the right side of the hood then the bottom of the box can be removed from inside the car there is a bolt that holds the blower motor assembly screwed from the inside of the car it is about in the center of the plastic grating, after you have removed this panel get some black 3 M sealing caulk it comes in strips, just lay it onto the caulk that is already in place make sure that you have cleaned the sealing surfaces before you add the new caulk, also test the flap vacuum pot that is inside the blower box now would be the time to replace the diaphram, once all of this is completed then carfully slide the bottom of the blower box into position then install the top of the blower box, then bolt everything back together you should see the new caulk squeeze out on the egdes of the blower box,then with a hose and some light pressure have a helper spray around the blower from under the hood to test your work, if you find a leak you may be able to tighten the blower box securing screws a little bit tighter, Good luck, Stan

gasmanstl

Cool tips guys, Thanks one and all:

Stan - It has been wet there a couple of times (carpet - but I do not see evidence of water evaporation/solids accumulation/staining on the wood of the cover, or anywhere on the CE). I will disassemble this. I once thought it might be the windshield leaking, but no matter how I ran water on the car,or for how long, I could not reproduce it. If it's dripping, doesn't that mean the A/C condensate pan is plugged? How nasty might this be to attempt to rectify, or at least to blow out the end of the hose with compressed air or something?


Dave and Alan: Hmmm. Sounds like it's controversial, and I should prolly replace the durned things anyway. Wonder how expensive. With the thought in mind that they should probably be replace anyways, maybe I'll try the stabilant...or maybe I'll be so tired of this thing in another couple of days, that I'd rather have a nice tabasco and LSD enema than to take the !@#$ things back apart anyway.

Oy. I'm now using a Dremel and the handheld-penciltype-extension thingie with a diamond-coated abrasive point to rough off all of the corrosion from EACH and EVERY contact blade on connectors A-W, or whatever they are. I'm up to "K." Nice and bright and shiny metal. Doing both sides of the things takes off about a thou and a half, according to a quick survey. Wanted to use a wire brush...but the only one that would FIT was made of BRASS...and no matter how long I held it on a blade, the brass was not hard enough to remove the corrosion. No way to get the steel ones in...but I don't think removing the thou or two will be a problem. That oxide coating on those blades is pretty tough. Gonna do the same thing to the plugs themselves as I did to the fuseholders.

I thought I had some good isopropanol around here, but I couldn't find it. So I bought a gallon of nearly anhydrous stuff from the electronics shop, 99.57% pure; I was impressed they had such good stuff. It'll make a great diluent for the stabilant, and it's plenty to wash the CE copiously a few times, which I have already done once.

Alan

Clay,
Replace any you aren't sure about. As Dave says once you wear through the contact surface layer they deteriorate quickly. They are plated mainly to ensure they stay oxide free. Copper or aluminum are great conductors but they oxidize rapidly, brass is less prone and used for plug-in terminals as is gold - at much higher expense.

In practice most relay contacts seem to be plated with some silvery finish - maybe its nickel - probably over a brass base. Both are hard and Nickel is quite resistant to oxidation and cheap. Filling a sealed relay can with Nitrogen or other inert gas would also be helpful for this.

Nickel can be polished to be very flat and since it stays oxide free quite well it will contact well over time.

When switching inductive loads - when the circuit is broken the current flow stops but the inductors magnetic flux wants to maintain the current flow - this causes high voltage spikes on the just barely opened contacts causing a temporary arc - this will act to damage the surface and eventually can cause a localized build up of surface debris - local oxides or surface material displaced as a result of arc superheating. Then next time the contacts open this area becomes a prime target since it now forms the closest spot between the contacts. This tends to cause accumulated localized damage and eventually the contacts don't close fully so these areas then carry the whole switched load causing further damage, possibly a high contact resistance OR localized heating can be sufficient to melt the intermediate materials and stick (weld) the contacts together.

If the original surface material is worn away by cleaning - the softer & more easily oxidized base layer will break down much more quickly under the same conditions...

So if you over-aggressively clean inductive load relay contacts you may make things worse, or at least only very temporarily better... If you leave surface irregularities (e.g. with coarse sandpaper) this will also further increase the rate of future degradation.

Relays that switch heavy inductive loads should however have design features like larger opening springs, wipe style contacts and other helper elements like resistor/diode networks to shunt inductor collapse currents to the supply rails to limit voltage levels & arcing...

Porsche does not do much to address this outside the relays (so you can just think of them as long term consumables!)

So look and see that the contact surface is still smooth/shiny & has not worn through to the base layer, if no its probably still good - just make sure its really really smooth.

Alan

SharkSkin

I don't think there's a controversy per se -- Maybe Alan was just unaware of that limitation of Stabilant. It's a highly engineered product and as such I consider their app notes to be the last word on details like this.

Alan's posted good info on relay contacts, no need to repeat it. Go ahead and clean them as you see fit, but you might want to prioritize the ones you've cleaned and replace them as you are able. For example, the horn relay may not be a high priority, but it's cheap. Fuel pump relay is more expensive and should be at the top of the list if you've had to file it down.

I used a carbon steel wire brush in the dremel, like the one in the pic below:

gasmanstl

Oh...I partially misread Alan's post following your initial one that said stabilant was not appropriate for contacts switching inductive loads. Now I get it. 'K...no stabilant on those.

Yeah, that's the wire brush I tried to use after the brass one failed...but it's so big, it is excedingly difficult to use, so I opted for the other thing.

Back to work...