Hi All.

I just bought a 2005 S40. On the test drive the brakes were not working correctly, with a soft pedal that almost goes to the floor. The car was priced correctly so I bought the car and carefully drove it home.

I have removed all the wheels and the rear driver’s side (left hand drive USA car) brake isn’t working. I thought it might be a stuck caliper piston, but the brake works when you use the hand brake?

I tried to bleed the brakes and I was able to get dirty fluid out of the 3 working brakes but no fluid out of the rear driver’s side caliper.

I used 32oz of new dot 4 brake fluid to try to clear out the dirty fluid but still no luck with the rear driver’s side caliper.

Thinking that the blockage might be in the caliper, I disconnected the pipe near the rear wheel, and stamped on the brakes, but no fluid came out?

The brake pipe is hidden under the car, but there appears to be no damage under the car so the pipe hasn’t been kinked.

What part is failing? Master cylinder? Abs? or ?

I don’t know if this is relevant but…. The previous owner had been told that the car wouldn’t pass emissions as the vacuum pump needed to be replaced at a cost of $1400. She decided to just sell the car. However the pump appears to be working and the car passed the emissions test. The garage might have just been trying to relieve the older lady of $1400. There is a noise coming from somewhere close to the oil filter, I read that S40’s are known to have issues with vacuum leaks close to the oil filter. Would that cause the brake issue?

Thanks

 

A stuck ABS valve might do that.

 

Is there a procedure to unstuck it?

 

Yep, buy a replacement abs unit. I went used for my S40 and the part cost me $65.

 

Did you also have the soft pedal and did the new/replacement abs unit cure the soft pedal?

thx

 

If you had a DICE / VIDA unit you could turn on/off each of the ABS circuits - I suspect you'd figure it out pretty quickly then.

Barring that, I did see a procedure that kinda/sorta makes sense. Doesn't sound like there's much to lose, and it might well break loose something that's stuck due to inactivity (my bet is that the car sat for a long time prior to your purchase). Here's a copy/paste of the procedure (copied from the Matthews Volvo site):

It's messy and you should wear eye protection: Have someone sit in car with key on so elec vac pump will work for brake booster to work. Break the line loose at master cylinder for the circuit affected and then snug it back. Have the wrench on that line positioned where you can move it 1/4 turn or more. Have the bleeder screws open on the blocked circuit when you do this.
Have assistant apply brake pedal hard and then you pop that line open 1/4 turn. Repeat this.
Often this will create enough pressure "shock" to free up the valve.
This isn't always successful but it going to cost you only the lost brake fluid.
If it works then bleed the brakes thoroughly.

 

I visited the scrap yard/auto recycler and bought a "new to me" brake master cylinder and abs unit. I installed everything and the pedal is now hard and all four calipers are working, BUT THE CAR WILL NOT START… I GET A WARNING SIGN “immobilizer see manual”

It appears that the main computer looks at the abs serial number and if it is different from the original it won’t start the car…. What do I do to correct this?

Any help would be greatly appreciated.

 

I kinda/sorta understand the reason for making the steering column lock coded to the car, but for the life of me can't figure out why an ABS control unit would be. That's not saying it isn't... but it would be a strange thing to do (even for Volvo, which is saying something)!

I agree with the poster on the other thread you just started - I'd try disconnecting the battery for a while. Or, just for giggles, you might try plugging in (but not plumbing) the old ABS unit just to see if that allows the car to start. If it does, you'd probably be locked into a trip to your local Volvo dealer for a little programming work.

 

Update


I found some info online that confirmed that the main computer in the car talks to the abs and as the serial number on the new/used ABS is different from the original serial number the main computer will not allow the car to start. The main computer needs to be re-programed to accept the new abs serial number.

I have a local garage that specializes in Volvo’s and Saab’s so I talked with them to see if they could re-program my computer. They informed me that it has to be done at the dealer and that the dealer will rip me off. Lovely…

The abs unit consists of three main sections, one section is the electronics and that section contains the electronic serial number.

I took the old abs unit apart

I took the new to me abs unit apart

I put the original electronic part on the new to me abs unit and put it in the car.

WOW it appears to have worked, the car will now start and the brakes are working with no abs light.

Now onto the suspension noise. I may be posting another question about that.

 

I pretty much have the same situation on a 2007 xc70. It all started with right front and left rear brakes locking up for about 15 seconds after pedal was released.l replaced all four calipers,rotor,pads, rubber hoses. They where all 14 years old .The brakes still locked up as before.Next I replaced master cylinder and brake booster. Still they locked up even with the abs module disconnected. Next I replaced the hydraulic block with exact matching one I bought on eBay. The brakes no longer locked up but I had no brakes or fluid to right rear wheel so I sent my original hydraulic block and pump off to have it rebuilt, got it back and installed it, now I don’t have fluid or brakes at the left front wheel.I’ve tried vacuum bleeding, pressure bleeding and good old fashion pumping and releasing bleeder valve. It’s driving me out of my mind.What am I missing?

 

Sounds like you need to back up a few steps and work "front to rear". 1) did you bench bleed the master when it was replaced? Do you see fluid coming out all the appropriate ports? 2) whats going on at the ABS valve body? did you check to see if you are getting fluid into the fill ports and out of the ports going to the wheels? 3) what's going on at the wheels? do you get fluid out of the lines at each corner? Once you see you are getting fluid, then you can work on getting any remaining air out.

 

Swop the Electronic component that was fitted originally to the vehicle with the second-hand purchased, the electronic unit is married electronically to the ECU. this is done with one long screw accessible via the valve body.
worked on mine.

 

+1 - the ABS valve body and the controller are just bolted together.