Electric Vacum Pump Conversion Finished

Peroni

Member
Joined
May 18, 2011
Messages
356
Reaction score
1
Location
North Carolina
Since converting to hydroboost my vacuum pump only worked the HVAC controls. For years this worked fine and I never experienced any issues with the mechanical pump. Relocating my power steering reservoir next to the a/c compressor led to me looking to make some more room in this area. Taking out the mechanical pump sure would free up a lot of room here.

I want to add this warning before going further. The SD vacuum pump will not work if you have vacuum assist brakes! This is only for those who have already gone to hydroboost brakes. The little pump will run HVAC controls just fine but not your brake booster. There are electric vacuum pumps out there that will power both but that is outside the scope of this write up.

I chose to use a stock SD electric vacuum pump MC# BRPV7. Looking around I decided to put it behind the coolant expansion tank. Examining the bracket the easiest way to mount this was to bend the little bent tab so it was flat again and drill it for a M6 bolt. The expansion tank bracket was removed, the hole locations marked and drilled/tapped. The pump fits perfectly in this space with plenty of clearance for the hood spring. Next I removed the low vacuum switch and manifold from driver side fender, ditched the manifold and moved switch over to just behind the pump. As it is a very light part I used a single bolt in one of the holes that previously held the jack retainer clamp. Again it fits in the spot perfect.

KMPQnuH.jpg


MKZziSQ.jpg




A new vacuum check valve is required and I found MC# YG429 that was both the correct size and right number of barbs. A small tee was put in the line coming from the pump and I ran that branch to the low vacuum switch. A simple adapter was turned to step up to the larger hose size the switch uses.

JrdhKe7.jpg


Wiring was straight forward. I simply cut and spliced the vacuum switch connector and ran it across the engine bay along with the pump power and ground wires. The pump connector is MC # WPT169. This is a generic connector used in other places and has 4 wires, only 2 will be used here. I took power from the under hood fuse box for now, used an add a circuit on the trailer battery charging fuse. I'm not thrilled with the arrangement and will eventually add a dedicated fuse for the pump for a more factory look.

The pump has its own built in vacuum switch, it will cut on and off on its own. It did not run for very long to draw down the system and I got several cycles of my HVAC switch before the pump came on again. I can hear it hum in the cab with engine off but when the engine is running I couldn't hear it.

Now that the new pump is in place, what to do with the stock pump - its removal to free up space was the whole point of this endeavor. I read some old threads where the pump was removed and a shorter belt used. That would lead to less belt wrap on the a/c compressor and p/s pump neither of which I was happy about. I decided to make an idler using the old pump's bolt pattern and mounting bolts. The idler itself is MC # YS267 and is the same as the one above the tensioner. Used the same pulley bolt too. To compensate for the different pulley diameters I moved the idler position tangent to its contact point on the belt. The assembly fits and pulley lines up to the belt properly. Tons of room for my p/s reservoir now.

9DAxwUA.jpg


For a belt I'm using a Continental Elite 4081215X which is 121.5" long. Keep in mind I'm using a SD water pump pulley, the SD dual tensioner and DC Power alternator which has a smaller than stock pulley. With the new idler in place my tensioner indicates about 1/16 above the center mark which is exactly where it was with the mechanical pump in place.

So far I've put 300 miles on this conversion and no issues have come up. My new idler looks be working fine, belt is tracking straight and running silent. This was a fun little project that took about a weekend worth of working on it on and off. If you're looking to ditch the stock vacuum pump maybe this will give you a few ideas to try.
 

billmoody1

New member
Joined
Jun 7, 2011
Messages
7
Reaction score
0
Location
texas
idler

If there is any chance you would make the idler piece I would love to purchase one:bowfast: I have the screws and bolt and pulley already
 

Yacob454

New member
Joined
Oct 10, 2022
Messages
2
Reaction score
1
Location
Alaska
Since converting to hydroboost my vacuum pump only worked the HVAC controls. For years this worked fine and I never experienced any issues with the mechanical pump. Relocating my power steering reservoir next to the a/c compressor led to me looking to make some more room in this area. Taking out the mechanical pump sure would free up a lot of room here.

I want to add this warning before going further. The SD vacuum pump will not work if you have vacuum assist brakes! This is only for those who have already gone to hydroboost brakes. The little pump will run HVAC controls just fine but not your brake booster. There are electric vacuum pumps out there that will power both but that is outside the scope of this write up.

I chose to use a stock SD electric vacuum pump MC# BRPV7. Looking around I decided to put it behind the coolant expansion tank. Examining the bracket the easiest way to mount this was to bend the little bent tab so it was flat again and drill it for a M6 bolt. The expansion tank bracket was removed, the hole locations marked and drilled/tapped. The pump fits perfectly in this space with plenty of clearance for the hood spring. Next I removed the low vacuum switch and manifold from driver side fender, ditched the manifold and moved switch over to just behind the pump. As it is a very light part I used a single bolt in one of the holes that previously held the jack retainer clamp. Again it fits in the spot perfect.

View attachment 177385

View attachment 177386



A new vacuum check valve is required and I found MC# YG429 that was both the correct size and right number of barbs. A small tee was put in the line coming from the pump and I ran that branch to the low vacuum switch. A simple adapter was turned to step up to the larger hose size the switch uses.

View attachment 177387

Wiring was straight forward. I simply cut and spliced the vacuum switch connector and ran it across the engine bay along with the pump power and ground wires. The pump connector is MC # WPT169. This is a generic connector used in other places and has 4 wires, only 2 will be used here. I took power from the under hood fuse box for now, used an add a circuit on the trailer battery charging fuse. I'm not thrilled with the arrangement and will eventually add a dedicated fuse for the pump for a more factory look.

The pump has its own built in vacuum switch, it will cut on and off on its own. It did not run for very long to draw down the system and I got several cycles of my HVAC switch before the pump came on again. I can hear it hum in the cab with engine off but when the engine is running I couldn't hear it.

Now that the new pump is in place, what to do with the stock pump - its removal to free up space was the whole point of this endeavor. I read some old threads where the pump was removed and a shorter belt used. That would lead to less belt wrap on the a/c compressor and p/s pump neither of which I was happy about. I decided to make an idler using the old pump's bolt pattern and mounting bolts. The idler itself is MC # YS267 and is the same as the one above the tensioner. Used the same pulley bolt too. To compensate for the different pulley diameters I moved the idler position tangent to its contact point on the belt. The assembly fits and pulley lines up to the belt properly. Tons of room for my p/s reservoir now.

View attachment 177388

For a belt I'm using a Continental Elite 4081215X which is 121.5" long. Keep in mind I'm using a SD water pump pulley, the SD dual tensioner and DC Power alternator which has a smaller than stock pulley. With the new idler in place my tensioner indicates about 1/16 above the center mark which is exactly where it was with the mechanical pump in place.

So far I've put 300 miles on this conversion and no issues have come up. My new idler looks be working fine, belt is tracking straight and running silent. This was a fun little project that took about a weekend worth of working on it on and off. If you're looking to ditch the stock vacuum pump maybe this will give you a few ideas to try.
Did you machine that idler pulley mount yourself? If so do you have the dimensions or a cad drawing for it?



I appreciate it
 
Last edited:

Latest posts

Members online

Top