ABS question - no fluid from one port

[rodneygt]

I get no fluid to the port on the abs modulator valve where the brake line connects that goes to the left rear/driver's side (US) caliper.

Background:

This is my daughters car, which I bought at 75-80,000 miles and I'm pretty certain that the brakes worked fine then. It has 140,000 miles now. I almost never drive it but when I did one day, I thought the brakes were weak, which prompted me to change the pads. However the real problem was only having 3 brakes.

So, I changed the brake pads. I noticed the old pads on the driver side rear where substantially thicker than the passenger side. That caliper would not pump up. No fluid goes to it when you press the brake pedal.

So, I did the following tests: 1) Removed the rubber brake line from the caliper but got no fluid when the brake pedal was pressed. 2)Removed the rubber brake line from the metal brake line the the wheel well are but got no fluid when the brake pedal was pressed. 3) Disconnected where the metal brake line from the rear right caliper connects to to metal brake line that goes to block on the ABS unit but got no fluid when the brake pedal was pressed. 4) Disconnected the other end of that metal brake line from the block on the ABS unit but got no fluid when the brake pedal was pressed. And 5) as an added bonus, I checked and verified that both lines on the master cylinder had pressurized fluid when the pedal was pressed.

So, something is wrong in the ABS unit. But, I have no ABS or brake warning lights on the dash.


Has anyone heard of this and is it something that can be fixed without a new ABS unit? I emailed xemodex and they thought I might could just remove it and blow it out - they had apparently experienced something similar with BMWs.

I would appreciate any help. I've spent quite a bit of money on this car in the last year and I'm hoping this wont break the bank.

[rodneygt]

Here's a picture of the line that has no fluid - the one I marked in yellow. The picture turned sideways for some reason when I posted it, sorry.

[rodneygt]

One of the members on here pm'd me and gave me a lot of helpful advice.

I have good brakes again.

To get to the unit I removed the stabilizer bar that bolted on the the upper shock mounting areas (this is an option my daughter's car has, not all have it but there' a snap off cover on each side and 2 nuts under each cover - 13mm).

Then I removed the battery and battery box - cover, front half section of box, battery cables, 2 nuts (10mm iirc) holding battery hold down bracket, battery, 3 bolts (8 mm) from bottom of battery box and then the rest of the battery box. That gets you to where you can get to the abs unit as shown in the post 2 pic above.

The harness connector has two little tabs at the bottom you squeeze. Then you tilt that part up, which unlocks the connector so you can simply pull it off.

It was time consuming and a bit tedious getting the old unit disconnected/reconnected from/to the mc and brake lines and then out/back in but it wasn't that difficult. A stubby wrench makes life easier in getting the lines off and on.

There's one torx bolt you have to remove holding the abs units bracket to the car. The bracket is also connected by pins that simply slide out of a couple of grommets in the bracket. The brackets are a little different between various p1 cars.

I ordered a used abs unit off of eBay and swapped the modulator block out of it. I used the electronic control unit part and the pump motor off of my old unit, although I could have used the new pump motor. I was told that the electronic part is married to the car's ecm so I needed to use my old one.

Swapping the modulator valve block is easy peasy - two torx bolts through the pump motor housing holds all three parts together.

It took quite a bit of bleeding to get fluid at each corner. I attempted to use a mighty vac hand vacuum bleeder without much luck. I ended up getting my wife to work the pedal and two-person bleed it. And then I ended up bleeding a second time this morning. It seems good now and the hand brake works again.

I'm adding a couple of pics showing the two abs units and how they appear disassembled.

[RichieS40]

Hi,

Quick question - I want to get the electronic module off my 2007 S40 as I suspect I've got a bad solder connection in there somewhere throwing up an intermittent ABS warning light. When I separate the electronic module and aluminium hydraulic manifold by loosening the two pump bolts that go straight through, will I get immediate leaking?

i reckon I can create enough play in the rigid lines to give me the space I need to get the module out and I realise bleeding the system afterwards will be wise but could I e.g. Cable tie the pump to the block temporarily to minimise fluid loss or am I better off biting the bullet and disconnecting all the lines at the couplers to get it out comfortably?

[rodneygt]

I don't think you can leak any fluid unless you remove brake line(s). They're just dust sealed to the block I believe.