I'd like to get rid of the mechanical vacuum pump now that I've got hydroboost brakes. Got the electrical part and the electrical replacement pump part of the project figured out - I think.

Where I'm still struggling is with the remnants of the old vacuum pump. One obvious solution is to get rid of it altogether and find the correct shorter belt to just bypass it. TJBeggs commented in another thread that he didn't think there'd be enough wrap around the PS pump pulley without the vacuum pump there as an idler. He may be right but I remember reading somewhere that someone did it and it worked OK.

The other solution is to gut the old pump and install new bearings and use it as an idler. I'm sure this can and has been done, but it just doesn't seem right to have yet another idler pulley and bearings on the system.

Just wondering if anyone has any thoughts or has done the mechanical pump delete?

Thanks

 

I was trying to figure how to do this, because the reason the mechanical one fails is due to wear.
The bearings give out on them. There is oil inside the assembly.
I never did figure out a good way to switch it over to just an idler, but the one i was messing with to figure it out was completely trashed.

I'd love to do that conversion as well when i get the assembly to do it. I hate not having good brakes because i cannot keep a good vacuum on the truck. I've been tempted to add in an electrical vacuum to help keep the system better going so the other one doesnt work so damn hard and wear out as quick.

 

Thanks for your comments. I'll let you know if I make any progress on this. Right now I'm at the point where if I take anything more apart on my truck it may never run again...!

 

Totally understand.
I'm really jelly of your hydroboost htough.

I need to do this sometime soon. I'm just so sick of ****ty brakes.

 

SD 7.3s route right from the alternator (alt and A/C are switched places) to the P/S, with plenty of wrap around both. Come to think of it, I would reckon a belt length of about that used on the SD would be perfect for this.

 

Thanks. Would be great if the SD belt will work. I have an old broken belt I can try to wrap around everything to get a ballpark idea of the right length.

 

Did anyone come up with a solution yet? I have not had enough seat time with anything in tow to know how well the brakes work. where do i find this hydroboost ?

 

Why not bring a old vacuum pump to a fab shop and have them build you a bracket that would accept a standard ford idler pulley. It really wouldn't be that hard.

 

Not hard at all, I can build an idler pulley bracket myself, but my goal is to get rid of the mechanical vacuum pump and not replace it with an idler pulley. Trying to avoid adding one more idler bearing. They're pretty reliable but still, one more part to fail at some point.

 

Good idea. That is what I will do or I will build one. not sure. it would have to be perfectly aligned. This project is not even on my lest yet but never know.

 

Hay bob, how is this going? I was just on rockauto and seen a hydroboost setup. Is that what you have? it looks like you just bolt it on and wire it? cost like 225.00

 

Yes, that's what I have, still sitting in its box on a shelf. I got a Motorcraft electric vacuum pump but you can get a Doorman knockoff a lot cheaper. I also ordered the electrical connector.

Installing it and getting rid of the mechanical vacuum pump and finding the right belt is probably going to have to wait 'til winter. Just too much going on right now!

 

What is the round thing that looks like a electric motor on the hydroboost then? where do you mount the electric pump? is it always on or activated?

 

Just to make sure we're talking about the same thing, the device I'm talking about is a Super Duty electric vacuum pump. It's used with a hydroboost brake system, since with the with SD hydraulic brake booster, the braking system doesn't need vacuum anymore.

The electric vacuum pump from a Super Duty only provides vacuum to the AC and heater dashboard vents (not sure exactly how this system works). It doesn't provide any vacuum to the brake system since they are boosted by the power steering pump. The electric vacuum pump doesn't have the horsepower to make the vacuum brakes work. You need to have a SD hydroboost brake system to use the electric vacuum pump. You probably know all of the above, I just wanted to make sure because it can get confusing.

About your questions I think the round part of the electric vacuum pump is a DC motor, haven't torn one apart so don't know how they work. I'm not sure yet where I'm going to mount it. I'll have to look under a SD hood and see if the location they use will work with an OBS.

The electric vacuum pump is always ready to run when it has 12VDC but it is not always "on". It has an internal vacuum switch and when the vacuum gets to a certain point, the pump automatically turns on and will automatically turn off when it has generated enough vacuum.

 

The bearings get more load either in the pump or a gutted pump because the belt load on the pulley is an overhung load. The bearing on the pulley side sees more load than the belt pull and the outside bearing sees reverse load.

An idler puts the bearings inside the pulley. That lets the two bearings share the load and the load is in line with them. Idlers should last a really long dang time.