BJ40 1980 brake problems (2 Viewers)

[618Henrik]

Hi all, update
I received and mounted the mastervac and the brake calipers , but the brake pedal is always very hard ....
but I noticed that the suction coming directly from the tube of the vacuum pump without going through the vacuum reserve is higher than what I hear in the tube coming from the tank itself
could this be the cause of the problem?
can I connect the tube from the vacuum pump directly to the mastervac?
thank you

Giacomo

yes, you can connect the hose directly from the vacuum pump to the brakebooster.

Then, first and maybe second time you pres your foot down the pedal will be ok and the brakes will work. But third time it will be hard. Wait 4 seconds and it will work again.
Have been running my bj42 like that for years, never got around to mount the vacuum tank

 

[giacomo]

Thank you 618Henrick
in fact during the test in the first and second time of the pressure of the brake pedal the same was soft but already at the third it became very hard
but could it be a low depression due to a vacuum pump malfunction ?

Giacomo

 

[roscoFJ73]

Ive always thought of the vacuum tank as a back up safety device in case the engine cuts out and stops making vacuum. There is enough vacuum in the tank to bring the vehicle to a single stop. And the pumps I have looked at cut out at a certain point when the tank has max vacuum.

 

[618Henrik]

Thank you 618Henrick
in fact during the test in the first and second time of the pressure of the brake pedal the same was soft but already at the third it became very hard
but could it be a low depression due to a vacuum pump malfunction ?

Giacomo

If the brake pedal are normal/soft first 2 times and then become hard then the vacuum pump and the brake booster are functioning properly.
I would definitely try to find another vacuum tank, as others has mentioned it could just be at piece of pvc pipe the size of a vine bottle.

RoscoFJ73, you are absolutely right, the vacuum canister IS indeed a safety device and I would NOT recommend driving around without it. (do what I say, not what I do)

 

[giacomo]

If the brake pedal are normal/soft first 2 times and then become hard then the vacuum pump and the brake booster are functioning properly.
I would definitely try to find another vacuum tank, as others has mentioned it could just be at piece of pvc pipe the size of a vine bottle.

RoscoFJ73, you are absolutely right, the vacuum canister IS indeed a safety device and I would NOT recommend driving around without it. (do what I say, not what I do)

do you know what vacuum value I should measure with a pressure gauge?
the vacuum tank seems to me very difficult to find...
thank you

Giacomo

 

[618Henrik]

there are no numbers for the vacuum in any of the workshop manuals I have.

The vacuum tank is located under the driverside seat, bolted to the frame, and is very big, at least on a BJ42.
But you could source one from an old HJ60, there should be plenty of them around in Italy. Those tanks are much smaller, and fitted in the engine compartment, therefore they are not rusted.

btw, that 13B-T engine, do you have many of those in Italy?

 

[giacomo]

there are no numbers for the vacuum in any of the workshop manuals I have.

The vacuum tank is located under the driverside seat, bolted to the frame, and is very big, at least on a BJ42.
But you could source one from an old HJ60, there should be plenty of them around in Italy. Those tanks are much smaller, and fitted in the engine compartment, therefore they are not rusted.

btw, that 13B-T engine, do you have many of those in Italy?

but does the HJ60 vacuum tank have the low pressure switch ? or can he do without it ?

there are not many in Italy of 13B-T engines

Giacomo

 

[roscoFJ73]

but does the HJ60 vacuum tank have the low pressure switch ?

Yes , it has a low vacuum switch that makes your brake light come on.
I think it is located close to the brake booster. Probably where the fender meets the firewall. But I think it can vary depending on LH or RH drive

 

[roscoFJ73]

there are no numbers for the vacuum in any of the workshop manuals I have.

The figures for later models are measured from the vacuum pump. They have a cut off valve when a level of vacuum is reached. Mine is 6 but I forget what type of unit it is, it might have been 6 psi vacuum.

 

[fitzmooney]

My 60 has vacuum gauge fitted.
I get 26in/hg on a cold start and it drops back to about 23 when it gets hot after a few ks.

 

[giacomo]

The figures for later models are measured from the vacuum pump. They have a cut off valve when a level of vacuum is reached. Mine is 6 but I forget what type of unit it is, it might have been 6 psi vacuum.

Thank you

6 bar vacuum from the vacuum pump ?
do you have any pictures of the vacuum tank of a HJ 60 LHD ?

Giacomo

 

[fitzmooney]

26in/hg = 660mm/hg = 0.88bar

 

[fitzmooney]

It is impossible to get a good picture of my vacuum reservoir.
This link shows a drawing of it.
Mine is the larger one as I have a clutch booster.

BRAKE BOOSTER & VACUUM TUBE | POWER TRAIN/CHASSIS GROUP | HJ60LG-MNZW | LAND CRUISER | EU | Toyota | Catalog | PartSouq Auto Parts Around the World

 

[roscoFJ73]

do you have any pictures of the vacuum tank of a HJ 60 LHD ?

No. These are the part numbers . Doesnt seem to be LH or RH like the 7* series. But the tanks all look much the same but with different brackets to suit the body
44704-60130 W/CLUTCH BOOSTER
44704-60140

If you put the part numbers into google you will get diagrams, maybe even find one for sale. They are long lasting,so there should be plenty around.

 

[giacomo]

No. These are the part numbers . Doesnt seem to be LH or RH like the 7* series. But the tanks all look much the same but with different brackets to suit the body
44704-60130 W/CLUTCH BOOSTER
44704-60140

If you put the part numbers into google you will get diagrams, maybe even find one for sale. They are long lasting,so there should be plenty around.

Thank you all,
so it seems that the cause of the very hard brake pedal is precisely the vacuum reservoir.......
but does the size of the reservoir not affect the good functioning of the vacuum ?

Giacomo

 

[roscoFJ73]

Thank you all,
so it seems that the cause of the very hard brake pedal is precisely the vacuum reservoir.......
but does the size of the reservoir not affect the good functioning of the vacuum ?

Giacomo

Im not sure. It depends on how much vacuum they can store. I notice the older types are larger. The 105 series is even smaller than the 60 series, which is smaller than 40 series. I guess you would have to look at the pump specs for each model,.

 

[tornio]

HI GIACOMO , happy to hear you solved the problem , you can use as reservoire any kind of tank... and i personally don't have one on my bj.
a friend used an old little fire extinguisher tank that already has a tread connenction

 

[giacomo]

Hi tornio
problem solved thanks to your advice

after replacing the master cylinder and all the vacuum tubes, now the bj40 brakes
but I would also like to know what changes in terms of braking the transition from a master cylinder with 25.00 mm to 28.00 mm
thank you

Giacomo