ABS sensor leads

[ChrisWhewell]

I've seen a lot of talk about leads, what is the failure mode on those ?     When I changed a strut recently, the rubber outer coating on my one lead crumbled away.   Is the failure mode, that moisture gets in there and they corrode ?     Thanks !

[DAVES89]

That is pretty much exactly what happens. I sell both original condition and restored leads. I sell them for $125.00 delivered. If interested you can contact me at;

 lemke1044@aol.com

[ChrisWhewell]

Thanks, I'm going to give this a shot, just for the fun of it, will keep you in mind, thanks Dave    https://www.walgreens.com/store/c/flex-seal-liquid-rubber-sealant-coating-spray/ID=prod6105537-product

[DAVES89]

That could work and at the price is worth a try. Years ago I tried a product called "Plasti Dip". It would only last about 2 years. Then I hit upon the idea of taking off the plug and using heat shrink to restore the lead. If the sensor lead was crunbled like you said I would remove all the cracking rubber leaving me with just the braid. I would then install 1/4" vinyl tubing to cover the braid and then install the heat shrink.

 Good luck with your idea... 

 

[ChrisWhewell]

Yeah, I think I know what you mean, like, a can of stuff you can dip your pliers handles into and it coats them ... ?    That stuff in the link, I saw it on one of those cheap infomercials on the geriatric TV chanels.   If the failure mode is from moisture-induced corrosion, then any polymeric coating with integrity that can hold up under automotive conditions should work.   Maybe I could take a shrink wrap and  run a cut along its lenght, use that spray polymer stuff, and while its still curing, put the split shrink wrap over it, without using any heat, just as a protective layer.   And never let anybody see how pretty it doesn't look, hah

[DAVES89]

Using heat shrink that way won't work. Try the vinyl tubing and slit that. That way you have a foundation for the coating you want to use. It will still fail because you have to remove all the boots when you take off the plug. that way you get a seamless seal that will last for years.

 But it looks like you want to go a path I took years ago so good luck...

[DAVES89]

The leads are similar to coaxial cable. I have a number of leads where I cut them to install the heat shrink in the cracked areas and then used a coaxial splice with heat shrink over the splice. It is perfectly sealed but are unsaleable as a seamless lead is preferrred. I keep them for my own use.

 No idea of a "drain wire".

[KDirk]

Drain wire is just the shield around the inner conductor. This isn't electrically connected in this application, it is sometimes used in situations where better RFI/EMI immunity is desired in the cable so that it is less likely to pick up induced interference. Be careful with subbing other coax. 75 ohm is normal spec for TV signal and antenna applications. Some is 50 ohm and is typcially smaller diameter used with BNC connectors for amateur radio antenna lead ins and CCTV signal distribution among other things. The resistance seen by the EBCM on each lead circuit is somewhat critical so cable of improper impedance may well cause an issue where codes are thrown.

 

 

[KDirk]

Unless there is a magical invisible third terminal on each brake lead that breaks the drain wire out to the vehicle side harness and then on to a frame ground, no. Maybe it is one of those suppressed Tesla inventions, and inductive air ground. Actually, looking closer at the diagram now, it appears the drain on the vehicle side of the harness is tied to ground but has no continuity all the way to the sensor head (not connected through on the lead side of the connector in other words).

[padgett]

Can ground one side, has been working in cars for decades, all of my cars except the Judge have ABS now.

 

As to how it works, just look up Hall Effect.

 

I use Westmarine Liquid Rubber (resists corrosive elements) but they have a smaller tin with a brush in the store.

http://www.westmarine.com/buy/west-marine--liquid-rubber--P010_301_007_508

 

ps just crackibng/crumbling rubber is not an issue as long as the drain/ground/shield weave is not compromised.

 

pps most common failure is the fronts near the fenderwell where it flexes.

Edited September 11, 2016 by padgett (see edit history)

[Machiner 55]

Quote

(Thanks to ROJ for photo)

You failed to thank me for the use of my hand.

 

John F.

[ChrisWhewell]

How about..... a special black electrical tape.   You wrap it around a length of wire in the usual spiral fashion, and afterwards hit it with a heat gun and it constritcts responsively to the heat,  just like a shrink tubing.    Does that exist yet ?

[KDirk]

I've not seen heat shrink tape, though that would end up with to many lap joints to stay impervious to moisture for very long anyway. There is self fusing tape (also called self amalgamating tape or cold fusion tape) that is a non-adehsive rubber tape that fuses to itself when overlapped. Interesting stuff and has its uses, but brake leads are not an application I'd consider it useful for.

 

Dave is using a special high-shrink ratio tubing with an adhesive inner liner. About the best repair you could hope to get that will remain pliable and keep out moisture contamination. This is the only way I can see doing a decent repair with any longevity, unless you have a magic technique for applying new insulation on old wire.