- Posts
- 10,639
- Location
- Oxfordshire
Some info for anyone interested in converting none power assisted brakes to powered but the engine doesn't have oil lines or create a vacuum. I'm also using this as a notepad for myself 
This is what I have picked up and might not be accurate.
Hella UP28 pumps seem to be used quite a lot as OEM parts in the UK as an assist. They produce around -15 Hg (inch) . VAG/Merc/Jag/BMW/Electric cars etc. If you go look at the images on ebay, they are very easy to spot. UP30/32 are better and for use for fully creating vacuums, but I haven't seen them around in the UK.
You are looking for a vacuum of around -20 to -24 Hg (I've also read upto -30).
Do not wire them in to run continuously as.. well.. you'll end their life quickly.
People have wired them to switch on via the brake light.. I don't think this is a great idea as it takes a good few seconds to create the vacuum. You will be playing a game of 'will the pump create the vacuum before the brakes use it all', also when you start up you'll need to turn the brake light on for few seconds to get assisted braking.
I would prefer to have the pump create the correct vacuum when needed
Your best bet seems to be vacuum pressure switch that lets you adjust upto -24 to -30ish Hg. So, a tube from the servo to a 3 way junction. One goes to the vacuum switch, the last one goes to a non return valve and from that to the pump. Reason being, is that these types of pumps can leak, which would cause a drop of pressure to the switch which activates the pump. Confused? good.
(Note, If you have a vacuum switch built into your servo then use that to control the pump.)
Then wire it up so it uses a live that is on when the engine is on. So, when you start the car, the switch detects a poor vacuum, switches the pump on and you are good to go. If you require more 'pedal presses' between the pump activating or want to hook it up to more vacuum devices, then stick a reservoir in the system, else it isn't needed. Also people have made reservoirs from fire extinguishers (seems like overkill) to using pvc pipes with caps glued on.
Hope that made sense and someone finds it useful. I've found loads of pumps on ebay ranging from £30 to £160. You can pickup the switches from a few places too, farnell/rs also have them for around 15quid. You can buy kits for £200 quid.
Update
I've gotten hold of two up28's.. I'm going to experiment and see if they are enough.
As a bit of background, when I bought my 110, someone had replaced the engine with a 2.25d which doesn't generate a vacuum (sod butterfly setup). So they had disconnected the vacuum pipe. The brakes pass an mot but they are heavy. So I'm either going to create a leccy setup, switch the servo or get a new engine
Btw, I'm not going to drive around with dodgy brakes. If I go the electric setup, I'll visit the guy at the local garage and get him to do a brake test and measure the performance and have a butchers. The risk isn't worth it.
This is what I have picked up and might not be accurate.
Hella UP28 pumps seem to be used quite a lot as OEM parts in the UK as an assist. They produce around -15 Hg (inch) . VAG/Merc/Jag/BMW/Electric cars etc. If you go look at the images on ebay, they are very easy to spot. UP30/32 are better and for use for fully creating vacuums, but I haven't seen them around in the UK.
You are looking for a vacuum of around -20 to -24 Hg (I've also read upto -30).
Do not wire them in to run continuously as.. well.. you'll end their life quickly.
People have wired them to switch on via the brake light.. I don't think this is a great idea as it takes a good few seconds to create the vacuum. You will be playing a game of 'will the pump create the vacuum before the brakes use it all', also when you start up you'll need to turn the brake light on for few seconds to get assisted braking.
I would prefer to have the pump create the correct vacuum when needed
Your best bet seems to be vacuum pressure switch that lets you adjust upto -24 to -30ish Hg. So, a tube from the servo to a 3 way junction. One goes to the vacuum switch, the last one goes to a non return valve and from that to the pump. Reason being, is that these types of pumps can leak, which would cause a drop of pressure to the switch which activates the pump. Confused? good.
(Note, If you have a vacuum switch built into your servo then use that to control the pump.)
Then wire it up so it uses a live that is on when the engine is on. So, when you start the car, the switch detects a poor vacuum, switches the pump on and you are good to go. If you require more 'pedal presses' between the pump activating or want to hook it up to more vacuum devices, then stick a reservoir in the system, else it isn't needed. Also people have made reservoirs from fire extinguishers (seems like overkill) to using pvc pipes with caps glued on.
Hope that made sense and someone finds it useful. I've found loads of pumps on ebay ranging from £30 to £160. You can pickup the switches from a few places too, farnell/rs also have them for around 15quid. You can buy kits for £200 quid.
Update
I've gotten hold of two up28's.. I'm going to experiment and see if they are enough.
As a bit of background, when I bought my 110, someone had replaced the engine with a 2.25d which doesn't generate a vacuum (sod butterfly setup). So they had disconnected the vacuum pipe. The brakes pass an mot but they are heavy. So I'm either going to create a leccy setup, switch the servo or get a new engine
Btw, I'm not going to drive around with dodgy brakes. If I go the electric setup, I'll visit the guy at the local garage and get him to do a brake test and measure the performance and have a butchers. The risk isn't worth it.
Last edited:
