ABS control unit repair

[RiPsTa33]

http://www.volvoforums.org.uk/showthread.php?t=72655

[Yog Sothoth]

hope it’s ok to revive this old thread.
I tried the self-repair of the ABS module from my ‘98 V70r as it failed MOT. All was going ok but in getting the lid off the box, I dislodged a component on the board. 😭
Does anyone know if that means it’s a write-off, or would it be feasible to replace said component (or get a competent electronics technician to do it)?

[DaveNP]

IMHO
It would depend on what the component is, if it's a simple component like a resistor or capacitor shouldn't be too hard, a more complex component like a processor chip makes it much more risky; similarly if the component is damaged simple components simple to replace, complex components practically impossible to replace. I'd say at this point it rapidly becomes simpler to get hold of a secondhand unit from a breaker.

[Yog Sothoth]

After a bit of googling, it seems it’s an electrolytic capacitor. I will take it to the electronics guys at work and ask if it’s replaceable.
Am I right in thinking that a replacement unit has to be the exact same component number and has to be both pump and ECU, or they won’t be compatible?

[Martin Cox]

Yes, it's a 22uF 35V electrolytic capacitor. The component cost should be mimimal; a matter of pence. Anybody who's used to working on surface mount printed circuit boards ought to be able to do it although the Conformol coating can make it a little more difficult. It's the sort of thing I occasionally do myself at work but I'm not sure I'd want to tackle it at home.

[Bob Meadows]

Martin: ~
Question if you can help please: ~ I have done a repair on the ABS unit (’97 V70)
The top coating was just peeled back for soldering and then on completion folded back- the unit is sealed around the cover & taped with a waterproof product.
In your opinion how important is it to reinstate the Conformol coating & would the attached product be ok?

https://www.ebay.co.uk/itm/10ml-conf...f/254181414540

Thanks Bob.

[Martin Cox]

Ideally I'd think one should replace the Conformol coating but I'm no expert.

I've no experience of the product you suggest but I should think it would do the job. It may also be worth looking at RS components or Farnell since it's likely they'd do something suitable too.

I repaired my ABS module about 10 years ago and I didn't bother to replace the Conformol coating. I did remove as little of it as practical and to date I haven't had any further trouble. I suspect that if you can effectively reseal the module it may not matter too much.

Martin

[amazondean]

I have managed to salvage my abs module by just heating up the two pins where the connector goes into and melting the solder under these pins without opening the unit. I read about this once before and it actually worked for me. A result I wasn't expecting!

[Cookeh]

Interesting. That is a viable method on thicker pins, but it's not often that the power supply pins go.

[amazondean]

I had read that it is usually the power pin joints that go because when they were soldered at the factory it was these that did not get enough heat for the solder to stick properly, due to the heat going up the pins. Anyway, It worked for me.