Another problem I could really use some help with. My 2001 S40 has a hard brake pedal after sitting a while when first started. If I let it run for 5 minutes it seems to be less of a problem. I have checked for a possible vacuum leak, and came up with nothing. I could use some advise on what to check next.

 

I have a 2000 S40 with the same issue on start up. I have an alldata subcription and it seems that the system uses an electric vacuum pump to generate vacuum for the power booster when needed (i.e. under turbo boost). According to alldata there was a recall associated with a hard pedal condition. Below is an excert taken from the TSB:

Background:
Volvo Cars North America LLC (Volvo) has decided that a defect related to motor vehicle safety exists in certain model year 2000 S40 and V40 vehicles. Under certain circumstances, water may enter the electrical brake vacuum pump, causing the pump to not function. This will require more brake force to stop the vehicle. However, this is primarily noticed at cold start. This limited braking power can affect the vehicle's stopping performance.
The corrective action will be to replace the vacuum pump with a new pump of a modified design. This new pump will be placed in a new location to prevent water intrusion.

The recall number is 5520011.

I will calll the dealer and try to get a lil bit more info. Hopefully other people will chime in if they have a similar issue and have it resolved.

Thanks,

Brock

 

On 2001 and up you should have the redesigned system.

The part that fails you is the vacuum pressure switch. It is located on the Brake Booster around 11 o'clock and has a two wire connector. You can verify the pump is okay by shorting the connector. You should hear the pump run.
You have to buy the entire hardpipe/hose that the vac switch is attached to ($90), but if you are looking for a cheaper fix, you can steal the switch portion off the hose from a junkyard car... V70's and other models also have this switch you can use, it is located behind the drivers headlight though. It pops off the hose with a flat edge screwdriver.

 

Thank you for your help. The Vacuum Pressure Switch repaired the issue.

 

No problem

 

Hey guys i have the same exact issue, this all started when i changed my pads, but during the bleeding the front left caliper's bleeding screw broke so i had to get another caliper during that time i had to leave the hose out so some air must have gotten in it. when i replaced the caliper i bleeded the whole thing again. then i came across this same issue ... the pedal is hard and it doesnt stop, it needs to be warmed up at first. today the mechanic told me its the brake vacuum pump.. which i assume is the booster.. i have a 2001 s40 i wonder if this will fall under the 2000's recall maybe based on the time it was manufactured?
anyways i wonder if i need to replace the whole brake booster which is expensive or can i do that switch thing?

Thanks

 

superbovine (or anyone else): I have 2001 S40 and need to replace the vacuum booster switch. This post covered the issue but the detail on the switch replace is what I'd like more of.

Do you have any suggestions or precautions for removing the vacuum booster switch (the one at 11 oclock on the booster with the 3 hose lines and connector). My switch was missing it's 'top cap' and the spring exposed. I bought a new one from volvo, but replacing seems like a 'one-time-thing' and I don't want to screw this up.

It looks like it just unplugs from the vacuum booster, but the long tube with the brass insert section at the front is the biggest unknown. Is there a retainer/nut(?) that I don't see or is it really just twist and pull/push.

 

Given that I didn't want to mess up a $150 dollar purchase of the volvo factory part, I was a little hesitant to just pull and replace... so for anyone out there that might be similarily hesitant -it turned out that the brass end of the vacuum switch line inserts into a plastic sleeve, mine was sticking after all these years, but once you remove the switch from the vaccum pump (just pull out) and uncoupled the short lines' connector green clip, you only have to unravel the line from the "cluster-f*" and twist the brass end a bit and gently pull/twist/repeat until the brass removes from the insert. replacement is same.

Brakes are spot on now.

 

Hello All,

Hate to awaken an old topic, but does anybody have a part# for the Vacuum Switch assembly. I have a 2000 S40 that looks like it has the retrofit kit installed. However I just started getting a hard pedal after the car sits awhile. After a couple of minutes, brake pedal is fine. Anyway, I think the switch has gone bad. I do an OHM test on the switch with engine not running and I get a full closed indication (Normal). As soon as I start the engine I get a Full open indication. I think the vacuum portion of the switch may be week and turning the pump off before there is sufficient vacuum for the brake booster. I should mention that when I start the car, the pump does turn on for about 2 seconds and then turns off and does not go again.