Brakes: Power wires insulation has crumbled away.

[Moose850]

I have to remove the ABS pump on. Any tips particularly when it comes to bleeding system after refit?

Can the plastic cap be removed as I need to fit two new power cables as the insulation has gone brittle and is crumbling off? These cable go up into the black plastic cap.

[Cookeh]

Originally Posted by Moose850

I have to remove the ABS pump on. Any tips particularly when it comes to bleeding system after refit?

Can the plastic cap be removed as I need to fit two new power cables as the insulation has gone brittle and is crumbling off? These cable go up into the black plastic cap.

Yes, it can be removed. Easy to remove when the pump is off, a nightmare in car. You can just cut these wires up towards the top end, add heatshrink and solder the join.

[Moose850]

Originally Posted by Cookeh

Yes, it can be removed. Easy to remove when the pump is off, a nightmare in car. You can just cut these wires up towards the top end, add heatshrink and solder the join.

That's good news. Any bleeding issues likey? None is this 'auto-bleed' using OBD scanner I hope like more modern stuff.

I normally start furthest wheel but someone said with Volvo you start nearest?

[Cookeh]

No idea, never had to remove a pump - so wouldn't like to comment.

[Moose850]

I removed the three torx screws that hold the unit to its mounting bracket and unclipped the brake pipes on the firewall and it came away from the turret a good few inches without disconnecting brake lines or putting any stress on the brake lines at all. There is a technique to getting the top off - just s queeze inthe right place and a tease with a screwdriver.

The insulation had crumbled off each cable to about 3/4" from the top where they go into the motor so it was a good call to remove the cap, a 'short' would have happened sometime soon. It is obviously an age related problem so a god thing to keep an eye on. I check two other cars of similar age and both showed signs.

[Shinsplintz 101]

I've noticed the same thing on the last couple of pump units I've swapped out - must be the heat of the engine bay, or perhaps the heat generated by the current flowing through them when the pump motor is at full chat? Copious layers of elecrical insulation tape carefully applied also does a fine job if your nervous about cutting the supply cables to apply heatshrink.

Re: bleeding. Start on the O/S/R then N/S/R followed by O/S/F finishing N/S/F. I use a pressurised one man brake bleed kit & purge twice to be on the safe side. Brake fluid is cheap. Brake failure is not 😬.

Happy bleeding. Cheers

[Bob Meadows]

If you intend to bleed the system it is worth taking a close look at each bleed nipple to make sure that they can removed ie not rust bound:~

I have done this on the '97 V70 but decided to have a new set of nipples on hand- covering the header tank with a thin piece of plastic and then screwing the top on will eliminate most of the fluid loss if not all.
Also used the bleed pipe with integral one way valve (ebay) otherwise quite straight forward following the bleed sequence etc.
Bob.

[Moose850]

Originally Posted by Shinsplintz 101

I've noticed the same thing on the last couple of pump units I've swapped out - must be the heat of the engine bay, or perhaps the heat generated by the current flowing through them when the pump motor is at full chat? Copious layers of elecrical insulation tape carefully applied also does a fine job if your nervous about cutting the supply cables to apply heatshrink.

Re: bleeding. Start on the O/S/R then N/S/R followed by O/S/F finishing N/S/F. I use a pressurised one man brake bleed kit & purge twice to be on the safe side. Brake fluid is cheap. Brake failure is not 😬.

Happy bleeding. Cheers

I have no problem with cutting the cables, it was obvious this was the way forward after removing the pins from the connector. It was obvious with the size (ID) of the heat shrink tubing that you would need to use to fit over the pins there is no way shrink ratio would be enough.

I decided to remove the motor so I could do the soldering on the bench. With the motor removed I could see the bearing in the aluminium valve body that the motor shaft locates in which is set in a small well. There was a small amount of brake fluid in the well. I assume it should not be there and is probably getting past the seal on the two sprung loaded pistons that ride against the bearing.

Is 'a little' oil always going to happen or is it a no no and a sign the seals on the pistons are on the way out? I have no problem with the ABS and the only reason I am looking at it is because of the crumbling insulation on the power cables.

If I need to get the valve body reconditioned can you recommend where?

[Moose850]

Originally Posted by Bob Meadows

If you intend to bleed the system it is worth taking a close look at each bleed nipple to make sure that they can removed ie not rust bound:~

I have done this on the '97 V70 but decided to have a new set of nipples on hand- covering the header tank with a thin piece of plastic and then screwing the top on will eliminate most of the fluid loss if not all.
Also used the bleed pipe with integral one way valve (ebay) otherwise quite straight forward following the bleed sequence etc.
Bob.

Thanks Bob,

Alway keep nipple free, I release them everytime I service the brakes, plus laterly I have fitted s/steel nipples. Yep, got one of those One-Way bleed pipes.