Please explain how the vacuum tank on 3B works?

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Only difference I can think of would be volume of vacuum available to the system? Does the small one have a port for the vacuum sensor idiot light sending unit thingy?
 
Yes, has that sensor.

I'm doing the conversion you've done. Except I'm a few years behind. Going from HJ45 to BJ45.

I'm thinking the little round tank would be easier to deal with even though I have a brand new shiny Awl_TEQ tank on the shelf ;)

I'll have to see how much of the original HJ45 vacuum hard lines I can reuse and base the decision on that. Just wanted to see if there was non-obvious functional reason the 40 series tanks are 5x the volume.
 
RufusTheDufus said:
Maybe the earlier vacuum pumps didn't draw as hard and required a larger volume to compensate for the lower vacuum?
Click to expand...

I was thinking the same thing. I guess the secret would be in the vacuum pump and how much vacuum it can make.
 
I've been running the little tank with the NPR alternator for a couple weeks now. It seems normal to me. The brake system works the same as it did with the stock frame-mounted tank and the same alternator.
 
I actually just replaced the little tank with the old one I fixed and my brakes are back to normal. Maybe my little tank had a leak or the stock pump isn't enough to keep up?
 
Hi;
Newbie here, so sorry to dig up an old thread..
My HJ45 has no vacuum pump or reservoir, but the servo is connected to the inlet manifold. The brakes are very hard.
I can see that it should have the huge oval tank under the floor, and the pump on the alternator (both have long since been removed).
I'm not a purist (yet) so I'm planning to install a modern electric vacuum pump, and a modest reservoir, and my question is this:

Can anyone please tell me how this was originally all plumbed together?
Is it just a simple pipe connecting Pump-Tank-Servo with no valves?
Is the manifold connection needed, or was this just added when the pump was lost, and should I just remove this and blank it off?
 
45Dougal said:
Is it just a simple pipe connecting Pump-Tank-Servo with no valves?
Click to expand...

Yes, the pump should have a built in valve that senses how much vacuum is in the tank. When there is enough it stops making vacuum.
Diesels don't make a lot of vacuum in the manifold , this is why they have the vacuum pump . Its also why your brakes are very hard. So, block it off.
 
roscoFJ73 said:
Yes, the pump should have a built in valve that senses how much vacuum is in the tank. When there is enough it stops making vacuum.
Diesels don't make a lot of vacuum in the manifold , this is why they have the vacuum pump . Its also why your brakes are very hard. So, block it off.
Click to expand...
Ahh right, thanks! My electric pump and tank just arrived so great timing :)
 
I dont know about your electric pump. I was referring to the OEM pump that was originally there
 
There is a possibility that you have a micro rust hole in your reservoir. If you do not have the power to brake, it just doesn't feel right then the two hoses that connect to your tank need to be removed and connected to each other creating a loop. Then go for a short test drive and see if the first or second pump is like normal. If yes then there is a hole in your reservoir tank, I have a plastic one from a vw on another truck that works, on a 60 series they are much smaller and mounted on the dash. My preference is to mount them under hood if you go off-roading. If not you could easily build one with pic and glue.
 
Wayneraintree said:
Which electric pump did you go with?
Click to expand...
I bought a used pump on ebay which was from a fairly recent landrover iirc. I also bought a small reservoir from an Isuzu trooper, and a pressure switch from alibaba...
If you have the original reservoir and switch then you can wire a relay from it to control the pump.
All together it works pretty well.
 
I have the factory reservoir, I need to verify the switch, on my BJ45 I've run into poor luck with Toyota or aftermarket alternators. I also had to install an aftermarket wiring harness due to the EDIC wiring burning up and overall PO hacking so now I have modern fuses and wiring that can handle a higher amp alt. I installed a 160 amp 1-wire so now I am trying to figure out the vacuum system. I will look al landrover pumps if you have any more hints as to the year/model or #'s on the pump LMK and I do appreciate it. Did you install any warning indicator if you lose vacuum? I just realized what the buzzer component was near the cluster in my dash LOL
 
Wayneraintree said:
One like this? : 2005-2009 Power Brake Booster Vacuum Pump - LR3, Range Rover, Range Rover Sport - (4.0L, 4.2L, 4.4L) - SQJ500082 - https://www.roverlandparts.com/05-09-power-brak-boost-vacuum-pump-sqj500082.aspx

​

2005-2009 Power Brake Booster Vacuum Pump - LR3, Range Rover, Range Rover Sport - (4.0L, 4.2L, 4.4L) - SQJ500082​


Click to expand...
Yea it looks exactly like that.
When the vacuum pressure rises, the switch turns on the relay and the pump pulls it back down.
As a temporary workaround, I did just connect the pump to the brake lights so it recharges each time you brake - dirty but effective to get you moving short term
 
Does the 3B system have a pressure valve that prevents it from over pressurizing ? My oem res tank has a sensor on it but the copper tab is broken off so I guess I need to source a new sensor. What does the sensor do exactly?
If I wire the electric vacuum pump to the brake lights short term how will I know it will not over pressurize? Would the electric pump simply be connected to the feed hose on the original vacuum 3B system? I’ve blocked off the factory “out and in” on the 3B block with bolts and copper washers. The remaining parts of the oem system are the hard line to the res, the res, and hard line going into the brake booster. I have a vacuum gauge I want to add so I can monitor the level. Not sure how else to monitor the level to be aware of any drops in vacuum but open to ideas. Thanks in advance!
 
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