Warning/disclaimer: The information in this thread describes modifying your vehicles brake booster assist system. I am not responsible for any damage to the car, any loss of braking, or anything that may be caused as a result of you taking the actions in this post. Please proceed carefully.
I've seen a couple of threads that reference people deleting their brake booster vacuum pump. I was confused a bit by this and was asking myself questions like "is that safe?" And "will this change the car in any way?". Well, from my understanding, most vehicles do not come with a brake booster vacuum pump. The Ford Focus RS sold in Europe with the same T5 motor does not have a vacuum booster pump. The Mazdaspeed3 (different motor but many shared components) does not have a vacuum booster pump. Our cars do.
The purpose of this pump is to supply adequate vacuum to the brake booster (also known as brake assist) system in the event that the motor cannot generate enough vacuum to do so. Cases when this typically happens is if you lose power (engine shuts off) while driving and then attempt to use the brakes. The brakes will still work in this situation, but you will be using the full power of your foot and leg to do so, as the car will not assist you.
So why do our cars have it when most others don't? The answer… likely safety. Volvo, bring the safety minded branded that it is, has supplied us with such pump so that in the situation where the motor shuts off and you need braking assist power, you have it. Again, the Ford Focus RS sold in Europe with the same (mostly) T5 motor does not have a vacuum pump.
Many people on this forum have deleted their vacuum pump entirely. The reasoning behind this varies from person to person, but overall it seems that the general consensus is to delete the pump for looks and space. The pump makes the engine bay look cluttered, and many people have built custom air intakes with the airbox sitting right where the pump does.
Originally, I deleted the vacuum pump by modifying the stock hose that was included on the car so I could keep the check valve. I HIGHLY advise against this. The reasoning? If the check valve goes bad, you will likely lose your brake assist power. It is not uncommon for these valves to fail. It is recommended to replace with a straight vacuum line like I will show you.
I won't go into detail on how to remove the vacuum pump and it's mounting bracket for two reasons: 1 it's been documented before and 2, it's fairly self explanatory if you look at it, the bolts you need to remove are the only ones connected to it. If anyone has questions on this though, I can definitely update this here!
Now you can remove the rest of the vacuum hose that routes to the intake manifold, OTE pipe, and brake booster.
Once that's removed, go ahead and get your new vacuum hose. I chose a hose from Amazon. It is 12mm inside diameter. This is a little bit of a tight fit, but it gives me peace of mine knowing it won't come off easily. Here's what I ordered: Amazon.com: High Performance Silicone Vacuum Tubing Hose, ID 0.47" (12mm), OD 0.71" (18mm), 5 Feet per roll (1.5 Meter), Black 60 psi Maximum Pressure: Automotive
We need to cut the end of the existing vacuum hose that connects into the intake manifold so that we can reuse this piece for our new hose. I cut mine right around where the yellow arrow was below.
![Image]()
After that, insert the piece you just cut into your 12mm ID vacuum hose. I added a hose clamp on this just for extra safety, but it may not be needed.
Then, connect the other end to the brake booster vacuum hose that comes from the firewall. This is slightly larger than 12mm, so this will take some muscle to get on. I also included a hose clamp here just to be safe, but this piece likely doesn't need it since it'll fit on so tight.
Finally, we'll need to plug the OTE pipe with a cap where our old vacuum line used to connect to. This prevents dirty and unmetered air from getting into the engine. I bought a pack of vacuum plugs at Autozone here: https://www.autozone.com/ignition-t...routine-maintenance/vacuum-cap/dorman-autograde-assorted-vacuum-caps/365550_0_0 I can't remember what size I ended up using, but the kit includes one that slides right over this plug. I then used a zip tie wrapped around it to make it hard for it to slide off. This shouldn't come off, but if it does I'll likely switch it for a hose clamp.
And that's it! Driving the car around feels like normal, and myself (as well as others) have noted that boost feels like it builds slightly quicker, as well as the turbo noises being slightly louder as well. This all might just be a coincidence, but it could also be a result of this mod!
I did some tests with braking, and it all feels the same as it did before. The only time it feels different is if the car is turned off and you continue to press the brake, but it isn't often that the car dies on itself and you need to brake in an emergency. Even if you do, you CAN still stop the car, it just won't be assisted (again, like most cars on the road today).
![Image]()
The engine bay sure does look a lot cleaner! Now I need to sort out my air intake situation and move that ugly looking ECU bracket I made…
I think I covered anything here, but if I missed something or anyone has any questions, feel free to reach out!
Sent from my iPhone using Tapatalk
I've seen a couple of threads that reference people deleting their brake booster vacuum pump. I was confused a bit by this and was asking myself questions like "is that safe?" And "will this change the car in any way?". Well, from my understanding, most vehicles do not come with a brake booster vacuum pump. The Ford Focus RS sold in Europe with the same T5 motor does not have a vacuum booster pump. The Mazdaspeed3 (different motor but many shared components) does not have a vacuum booster pump. Our cars do.
The purpose of this pump is to supply adequate vacuum to the brake booster (also known as brake assist) system in the event that the motor cannot generate enough vacuum to do so. Cases when this typically happens is if you lose power (engine shuts off) while driving and then attempt to use the brakes. The brakes will still work in this situation, but you will be using the full power of your foot and leg to do so, as the car will not assist you.
So why do our cars have it when most others don't? The answer… likely safety. Volvo, bring the safety minded branded that it is, has supplied us with such pump so that in the situation where the motor shuts off and you need braking assist power, you have it. Again, the Ford Focus RS sold in Europe with the same (mostly) T5 motor does not have a vacuum pump.
Many people on this forum have deleted their vacuum pump entirely. The reasoning behind this varies from person to person, but overall it seems that the general consensus is to delete the pump for looks and space. The pump makes the engine bay look cluttered, and many people have built custom air intakes with the airbox sitting right where the pump does.
Originally, I deleted the vacuum pump by modifying the stock hose that was included on the car so I could keep the check valve. I HIGHLY advise against this. The reasoning? If the check valve goes bad, you will likely lose your brake assist power. It is not uncommon for these valves to fail. It is recommended to replace with a straight vacuum line like I will show you.
I won't go into detail on how to remove the vacuum pump and it's mounting bracket for two reasons: 1 it's been documented before and 2, it's fairly self explanatory if you look at it, the bolts you need to remove are the only ones connected to it. If anyone has questions on this though, I can definitely update this here!
Now you can remove the rest of the vacuum hose that routes to the intake manifold, OTE pipe, and brake booster.
Once that's removed, go ahead and get your new vacuum hose. I chose a hose from Amazon. It is 12mm inside diameter. This is a little bit of a tight fit, but it gives me peace of mine knowing it won't come off easily. Here's what I ordered: Amazon.com: High Performance Silicone Vacuum Tubing Hose, ID 0.47" (12mm), OD 0.71" (18mm), 5 Feet per roll (1.5 Meter), Black 60 psi Maximum Pressure: Automotive
We need to cut the end of the existing vacuum hose that connects into the intake manifold so that we can reuse this piece for our new hose. I cut mine right around where the yellow arrow was below.
After that, insert the piece you just cut into your 12mm ID vacuum hose. I added a hose clamp on this just for extra safety, but it may not be needed.
Then, connect the other end to the brake booster vacuum hose that comes from the firewall. This is slightly larger than 12mm, so this will take some muscle to get on. I also included a hose clamp here just to be safe, but this piece likely doesn't need it since it'll fit on so tight.
Finally, we'll need to plug the OTE pipe with a cap where our old vacuum line used to connect to. This prevents dirty and unmetered air from getting into the engine. I bought a pack of vacuum plugs at Autozone here: https://www.autozone.com/ignition-t...routine-maintenance/vacuum-cap/dorman-autograde-assorted-vacuum-caps/365550_0_0 I can't remember what size I ended up using, but the kit includes one that slides right over this plug. I then used a zip tie wrapped around it to make it hard for it to slide off. This shouldn't come off, but if it does I'll likely switch it for a hose clamp.
And that's it! Driving the car around feels like normal, and myself (as well as others) have noted that boost feels like it builds slightly quicker, as well as the turbo noises being slightly louder as well. This all might just be a coincidence, but it could also be a result of this mod!
I did some tests with braking, and it all feels the same as it did before. The only time it feels different is if the car is turned off and you continue to press the brake, but it isn't often that the car dies on itself and you need to brake in an emergency. Even if you do, you CAN still stop the car, it just won't be assisted (again, like most cars on the road today).
The engine bay sure does look a lot cleaner! Now I need to sort out my air intake situation and move that ugly looking ECU bracket I made…
I think I covered anything here, but if I missed something or anyone has any questions, feel free to reach out!
Sent from my iPhone using Tapatalk
. There are three check valves in the system - the one at the manifold, one at the pump, and the one before the booster. Same design valve as used back into the '80's on Volvos, never ever heard of one failing 'closed'. Inside is just a small spring and a rubber disc. Manifold vacuum pulls the disc against the spring pressure.
