BJ40 1980 brake problems (1 Viewer)

[giacomo]

Hi all,

BJ40 LV-KC 1980 and front disc brakes with hard pedal brake,
now because I can not find the booster assy brake I would like to know if I can to fit the version for front drum brakes
thank you

Giacomo

 

[alberta mac]

it could be your brake booster on the back of the alternator ! Your air reservoir is mounted to the frame under the drivers seat ! I'll bet their is a hole in it ! disconnect the two hoses and connect them together then start it up and let it run then step on the brake !
If it works then it's your air (vaccuum ) canister. or it could be the brushes on your vaccuum pump on the alternator.
Pushing the brake a second time right after the first will result in poor braking.
If it is the canister then get some pvc pipe 2'' or 3'' and make your own canister with the fittings for the hose to connect.
You can store this cannister under the hood as there is lots of room.
So why these things rust out is because there is a water relaease screw on the bottom to drain any accumulated condensation. This gets overlooked very easily. I had to rebuild mine !
Cheers
hope that helps !
ps. post up a pic of your cruiser !

 

[giacomo]

Thank you alberta mac
I believe it is not a vacuum problem as I removed the hose on the brake servo and there is suction......

Giacomo

 

[tornio]

hi giacomo, ciao , maybe a rear brake cylinder is stuck or even some front calipers...

hard pedal .. but it brakes?? i ask you that because many years ago i removed the rear brake line and i drived with only the front disk : the pedeal was hard and it had a very short stroke but it did the job ... i never crash into anybody heheh
from where in italy ?

nice bj !!

 

[giacomo]

Ciao tornio and thank you for answer
besides having a high and very hard brake pedal, it does not brake.......

from Roma

if you want to write in private in Italian this is my email :meraviglia.g@gmail.com

Giacomo

 

[tornio]

no problem , here if we solve the problem , the solution remain for all us...

the problem may be the mastervac or the master cylinder broken or the rear brake cylinder and the front calypers stucked

the answer to your qustion is YES you can use the mastervac of old bj series (all drum) with two "tank" , i did it many years ago when i put a front bj42 axle on my first 40 which had all drums . i did it without change anithing else...

many years later i discovered here on ih8mud that there are two little "valve" on the all drums master cylinder that retain the pressure to
"force" the brake shoes near the drum. this valve needs to be removed because the disk brake doesn't need it. you have to remove only the front "line" valve. sorry i don't rember the correct name of this "valve".

all that said to take a test you can use the old mastervac+mastercylìnder even without remove this little valve

let us know

ora in italiano , il problema potrebbe essere il mastervac (la membrana) , il cilindro maestro e/o i cilindretti posteriori e i pistoncini delle pinza anteriori bloccati.
comunque si puoi provare il mastervac + cilindro maestro della vecchia serie , funziona io l'ho gia fatto.
solo dovresti togliere una valvolina dalla linea che "alimenta i freni anteriori" che serve a tenere un po di pressione che serve per tenere le ganasce allargate vicino al tamburo.

per fare una prova montalo cosi come è dovrebbe funzionare ,
ciao in bocca al lupo

 

[giacomo]

Ciao stefano e grazie per la risposta
questa valvolina stà all'interno della pompa freni o lungo la linea che alimenta i freni a disco anteriori ?
purtroppo non ho mastervac e pompa freni della vecchia serie a 4 tamburi

Giacomo

 

[tornio]

all'interno della cilindro maestro, mi sembra di ricordare proprio davanti (prima) del foro filettato dovi si avvita il tubo freno che scende verso i freni.
prova a cercare "disk conversion" DOVRESTI TROVARE UN TREADH A RIGUARDO.

ma per fare la prova quella vecchia va benissimo COSI Com'è.

io per mastervac intedno la membrana a depressione che sta dietro il cilindro maestro dei freni , la padella attaccata alla paratia.
scusa le risposte sintetiche ma sto lavorando passo di tanto in tanto davanmti al pc
ciao

 

[giacomo]

all'interno della cilindro maestro, mi sembra di ricordare proprio davanti (prima) del foro filettato dovi si avvita il tubo freno che scende verso i freni.
prova a cercare "disk conversion" DOVRESTI TROVARE UN TREADH A RIGUARDO.

ma per fare la prova quella vecchia va benissimo COSI Com'è.

io per mastervac intedno la membrana a depressione che sta dietro il cilindro maestro dei freni , la padella attaccata alla paratia.
scusa le risposte sintetiche ma sto lavorando passo di tanto in tanto davanmti al pc
ciao

quale intendi nella foto allegata ?

 

[tornio]

il mastervac è la padella proprio dietro il serbatoio dell'olio.
questa è la pompa del freni a disco

 

[tornio]

... 13bt under the hood !!

this is not an all drum brake master cylinder ,

the mastervac is the the big pan behind the brake fluid tank , i think you can try the fisrt series

 

[giacomo]

Lo sò che quello è il mastervac o servofreno
ma tu hai detto " all'interno della cilindro maestro, mi sembra di ricordare proprio davanti (prima) del foro filettato dovi si avvita il tubo freno che scende verso i freni. "
quindi dove stà questa valvolina ?
mi sembrava di averlo scritto che ha i freni a disco anteriori ....

Giacomo

 

[fitzmooney]

How about using English, so most of us can follow the discussion.
Thanks

 

[tornio]

YES , you said it has a front disk brake axle and you posted the disk type pump so how can i show you where is ... this "relief valve" i was speaking about is located inside the cylinder , if i remember it is inside the hole where the hard line connect the cylinder

part 47290 - 47280

 

[tornio]

.. and like i said there are threads about it that explain better than me how they work
hope it helps

 

[giacomo]

Ok
you talk about another master cylinder ,not mine...
I can not find the threads, can you tell me one ?

Giacomo

 

[tornio]

exscuse me ... but i don't understand your question, you asked if it is possible to run an old type (all drum serie) brake cylinder / assy into a car with a a fron disk axle (2 th serie) , right ?

the answer in my opinion is YES (i did it and it run for long time in my car) .

the photo you posted is about a second serie , after 1980, so this pump is allready a disk type....

if you have a doubt that this pump you posted is defective (ok) you can try an old series pump ( your question) : yes and that is the schema i posted Yesterday

so what is , or where is your doubt?

to start to dissolve your doubt about the brake system IGNORE These "relief valve" and give a chance a this old type of brake pump
cylinder/mastervac

if doing this swap will solve your brake problem you can Always remove these "valve" in the future.

these valve are part 47290 - 47280 look at the schema i posted...

and off course you will have to remove only the front one's and these valve are not present in the pump/cylinder you posted off course.

 

[giacomo]

maybe I explained myself wrong
but I was asking if I could to fit an old type of mastervac and not brake pump.....
besides, I do not have an old-style brake pump to do a test

Giacomo

 

[tornio]

yes , you can !
check the bolt pattern of the pump and the mastervac if the are the same try !

 

[giacomo]

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