[cristian]

Greetings forumers, I have the following question:

I have a problem with the brakes on my FJ40 1981.

It's drum 4-wheel, double cylinder, brake pump FJ45 1 1 / 8 "dual booster tank and original http://www.toyodiy.com/parts/p_U_197...P-KK_4702.html

The brake pedal is quite rubbery, even though I have already purged (bleeding) throughout the system. When you step on the pedal for the first time, goes to the floor, give it 3 times and up, but becomes like glue. With the car running just a little improvement, but it happens the same, the pedal goes to floor and must be given about 3 times to climb. Similarly, almost nothing does not stop, we must tread very hard for half the brake pedal.

The Booster is new toyota original package, bought in consecionarios. The bomb apparently is in good condition, has no such escape, however new kit is original amount toyota. The bands are in good condition, they lack adjustment but not enough to have the pedal on the floor and I do not think that this will influence paresca a paste.

advising?

[dgangle]

assuming no air in system, MC and booster good with correct pushrod adjustment, pure symptoms of incorrectly adjusted drum brakes. manually adjust all again...do both wheel cylinders/wheel until they drag slightly

how long have you had it and how long has it been doing this? what is a 'bomb"?

[cristian]

Originally Posted by dgangle

assuming no air in system, MC and booster good with correct pushrod adjustment, pure symptoms of incorrectly adjusted drum brakes. manually adjust all again...do both wheel cylinders/wheel until they drag slightly

how long have you had it and how long has it been doing this? what is a 'bomb"?

Hi, excuse my bad English, the pump is the master cylinder. Here in Venezuela we called pump brakes, but I wrote incorrectly "bomb". The fault is more or less a week, I do not understand is because the pedal is as hard after such a purge.

[dgangle]

no problem on your english. Adjust all your drum wheel cylinders, again, correctly this time

[lostmarbles]

x 2 on adjustment.

The wheel cylinders are large and require a lot of fluid to push out the brake shoes (- even to push them out just a few millimetres).

And the curvature of your brake linings must match the curvature of your drums. (Linings wear more on their leading edges tending to make their curvature poorly matched to the curvature of their mating drums.) ........Replace the linings if they mate badly (irrespective of the amount of thickness left).

Use a stubby screwdriver (inserted it into the access holes in your backing-plates) to "click" your adjustor notches TOWARDS your axles till the wheel becomes tight to turn. (Wheel jacked off the ground.) And then back off by 2 clicks. (Not 5 or whatever the FSM says.) Repeat for all adjustors on all wheels.

And if a lot of adjustment is being done - Get in the cab and jump on the brakes to recentre the shoes a few times during the process.

I avoid tightening the adjusters to the point where the wheels simply CANNOT be turned - because getting that wheel to free up again can be difficult (or time consuming).



PS. My experience is that brake shoes can have a lot of lining thickness left - yet still make adjustment difficult by having the curvature poorly-matched to their mating drum.

PPS. And this sort of thread usually gets a response of "change to disc brakes". But our drum brakes are actually great in my opinion - once you know their quirks.

[cristian]

Originally Posted by lostmarbles

...

PPS. And this sort of thread usually gets a response of "change to disc brakes". But our drum brakes are actually great in my opinion - once you know their quirks.

100% agree with you

thanks both!

[dgangle]

Originally Posted by lostmarbles

...And this sort of thread usually gets a response of "change to disc brakes".....

I was thinking it but resisted the temptation as while true, often isn't well-received.

Drum brakes, when working properly can considered adequate by some but that is subjective. It's that they have more moving parts and require more love, more often and have known operational disadvantages in certain circumstances.

I miss adjusting my brakes going on 9 years now.....NOT.

[cristian]

for an FJ40, with tires 33", drum on all 4 wheels and wheel cylinders 1 1/8", which is the best master cylinder?

master cylinder 1" or



master cylinder 1 1/8"

[cristian]

nobody??

[dgangle]

either will probably work. The larger dia bore MC pushes more fluid with the same linear movement as the smaller bore MC but with more pedal effort and will result in less pedal travel to accomplish the same thing as the relatively smaller 1" bore MC.

The question you should be asking yourself is 'what size MC did it have before and what problems am I trying to resolve with considering a different bore MC?' If you had a 1" and excessive pedal travel (assuming all manually-adjusted drum wheel cylinder operable and adjusted properly), then try the 1.125". If you had the 1.25" with a hard pedal (and booster working properly), then use the 1".

Remember that Toyota sent different braking systems on what we may consider similar trucks to different parts of the world so you may not get the exact answer you are looking for from someone say in the US, Europe, Asia, etc. Plus are you going to trust information on an internet forum from someone on the other side of the world? I question people's advice in the same town where I live.

Armed with some knowledge and understanding of how the systems work, get your answer by truthfully answering my original question.


.....AND buyer-beware if you buy anything from CCoT if you need non-standard application advice or any other form of customer service.

[cristian]

Originally Posted by dgangle

either will probably work. The larger dia bore MC pushes more fluid with the same linear movement as the smaller bore MC but with more pedal effort and will result in less pedal travel to accomplish the same thing as the relatively smaller 1" bore MC.

The question you should be asking yourself is 'what size MC did it have before and what problems am I trying to resolve with considering a different bore MC?' If you had a 1" and excessive pedal travel (assuming all manually-adjusted drum wheel cylinder operable and adjusted properly), then try the 1.125". If you had the 1.25" with a hard pedal (and booster working properly), then use the 1".

Remember that Toyota sent different braking systems on what we may consider similar trucks to different parts of the world so you may not get the exact answer you are looking for from someone say in the US, Europe, Asia, etc. Plus are you going to trust information on an internet forum from someone on the other side of the world? I question people's advice in the same town where I live.

Armed with some knowledge and understanding of how the systems work, get your answer by truthfully answering my original question.


.....AND buyer-beware if you buy anything from CCoT if you need non-standard application advice or any other form of customer service.

you're right, thanks

[nspctr1]

Did I miss something? I thought post 75 had front discs. was the axle swapped?

[lostmarbles]

Originally Posted by nspctr1

...I thought post 75 had front discs ....

USA-spec .....yes.

But this isn't a USA cruiser.

[cristian]

In Venezuela, the front discs came in the last year 85 model FJ40

[nspctr1]

Aahhh, I see. Then as mentioned above, it's probably the adjustment of the wheel cylinders that is not quite correct. They can be a booger to do and if they are not balanced then you can experience a pull to one side.

[cristian]

Originally Posted by nspctr1

Aahhh, I see. Then as mentioned above, it's probably the adjustment of the wheel cylinders that is not quite correct. They can be a booger to do and if they are not balanced then you can experience a pull to one side.

thanks buddy, but I adjust the bands and are well balanced. As I reviewed, the fault is being produced because the vent cap from the bottle of brake fluid is blocked, creating a vacuum and causes the air constantly soak the master cylinder.

P.S. excuse my bad English