Toyota~Boy

iTrader: (2)

87 Toyota 22r 5 speed..... Info in sig......

1st..... Okay I have had nothing but issues with my brakes since I've owned this truck. To start things off my front brakes intend to tighten up. I really don't know how to explain myself so bare with me. My brake petal use to get extremely tight at times. I could only push it down about 1/4 of a inch and my front brakes would lock up. Well I noticed if I'd pop my hood and pull the vacuum line off the booster my brakes would in freeze and be back to normal pedal. I I figured I had a faulty booster.
2nd...... Never had back brakes. So I bypassed the lSV in back and hooked them up like old school 50/50. Works great.
3rd..... So now I have really good brakes although my front ones still tighten up while driving.

So to make things short I upgraded my brakes to the 1" master cylinder and booster from a 95 4runner. At the same time I replaced all brakes.

Since then I have had excellent brakes until yesterday. I was driving home and I started loosing power and smelling my brakes burning. So I took truck out of gear and noticed I couldn't coast so I came to a stop beside road only to notice my front brakes were acting up again and the pedal was getting hard again. So I piped hood pulled off vacuum line and things were fine for a few more miles then I had to repeat process again.

All day today I've had to do the same thing with the vacuum line. It's starting to get irritating and I ruining my new front brakes.

Does anyone know what's wrong.

I have replaced the following things

Brakes
Calipers ( both )
Booster & master cylinder
Some brakes lines
Both rear slave cylinders
Bypassed that thingy on rear end ( LSV ???? )
What else is there to change that would affect this????

Please anyone that knows please share info. Thank you very much. I believe I will try just about anything to fix this............

timothy47129

Have you replaced the front rubber brake hoses?i think you have one or both hoses collapsing.Here is a text book description of how the brake booster works. if a driver applies 100 pounds of force on the brake pedal. The car has a pedal ratio of 7:1 and a 1” bore master cylinder. The car will make 891psi of brake pressure. If the same car were to add a 9” single diaphragm vacuum booster the brake pressure would increase by 899psi with a total brake pressure of 1790psi. But if you upgraded to a later booster you prob have a dual diaphagm and have a little more pressure.Im thinking with the booster disconnected the 891psi isnt enough to collapse the hose but the 1790psi with it connected is.

Toyota~Boy

iTrader: (2)

It done it before I switched over to later model parts. That was the whole reason I did the swap.

Yes both rubber front lines have been replaced. Since you mentioned that ima check them tomorrow when I drive it to notice if they have some defect that would be noticible when my brakes stick

timothy47129

you got me stumped then.Yeah when it does it see if the front rubber lines are hard to move or still soft.

wyoming9

iTrader: (1)

If it is both front calipers they could be both hanging up at once though that is doubtful .

For some reason the fluid is not returning to the master cylinder .

Are you seeing any brake fluid loss??

Is your brake pedal physically hanging up that it is not returning all the way??

If the piston travel in the master cylinder is not correct it allows fluid to get past the o rings which would not allow enough travel to release the front brakes completely.

96vettelt4

easiest just to pull everything off and check everything...something is sticking..

1986YODA

Just an off the wall suggestion about a funny brake incident I had. I had the same problem with a fiero had years ago.... Turned out the rubber brake line was old and would collapse when the fluid warmed up. Just something you might want to check

Toyota~Boy

iTrader: (2)

All these suggestions sound good. I'm getting ready to take off so I will check all of this as soon as it happens. Thanks for all info and I will keep ya posted

timothy47129

one more thing to check is your booster push rod adjustment.If there wasnt enough free play in the pushrod it could be causing the brakes to drag just enough that when the rotors get hot and expand its causing the brakes to drag.And when you remove vacuum line its giving it just enough freeplay to not drag as bad since the booster diaphram pulls the pushrod just a slight bit toward the master cylinder when its under vacuum.

Toyota~Boy

iTrader: (2)

Well with all the information I've gathered from you all and some local mechanics, everyone is kinda leaning toward the rubber hoses. So yesterday I bought to new rubber brake lines. Got them for $10.00 a piece. I have not put them on my truck yet. Although yesterday when my brakes started messing up and sticking I did check the hoses and they seemed to be fine. They didn't appear to be stiff or collapse although I am going to replace them. Tomorrow I plan on changing them so I will let everyone no if it fixes my brakes.

Toyota~Boy

iTrader: (2)

Okay..... So today I changed both front rubber brake lines. They seemed to be fine when I removed them but I went ahead and replaced them. To my surprise it did not fix my problem.

I called napa and ordered some replacement brake calibers. I can get brand new ones for $40.00 a piece. That's not remanufactured calibers. So went ahead and ordered those. They will be in tomorrow morning. So I guess I a change those now.

Anyone else got any ideas......

wyoming9

iTrader: (1)

Just maybe find out what is wrong!!

Or just keep throwing parts and hope you get it before you run out of money

Calipers are easy to check

So what is next

Toyota~Boy

iTrader: (2)

Well what's your suggestions ole buddy. You ever here of this problem.


On a second note what's that little valve looking thing that's connected into the brake booster intake vacuum. It's plastic looks like a check valve or sum thing. Does anyone know what it is or what it does. I haven't changed it yet

timothy47129

It's a 1 way check valve .after you start the truck and turn it off pull the line from the booster and if you hear it hiss the valve is working to hold vacuum in the booster.you should be able the remove it and try to blow through it the opposite way too and make sure the valves sealing in it

wyoming9

iTrader: (1)

Yes I have seen your problem several times!!!

How Long of a time and miles after the master cylinder and booster (Were these brand new??) swap was it all good??

I have never seen two calipers fail at the same time although it is possible.

I have gotten them to free up but most often it takes removing them from the vehicle and once they are seized they won`t release.

The Brake rule always comes into play what you do to the right you do to the left.

As I stated if both calipers are not hung up which seems to be the case as you are able to drive the vehicle normal at times . How long does removing the vacuum hose get your brakes working again a few minutes a few brake applications 50 to 100 miles???

The brake fluid is not being allowed to flow out of the caliper pistons

Why ?? It could be from several things could be as simple as a crushed line but then the problem would never go away.

Which points to me the o rings in the Master Cylinder or the linkage in the booster connecting to the brake pedal .

If you were not so far away i would be glad to help in person.

I hope your caliper replacement does the trick.

Good Luck:jessica:

Toyota~Boy

iTrader: (2)

Ok let me explain something: it is 11:25AM here. I have not started my truck today. I can go outside get in it and drive down the road and it will be fine for probably 15 maybe 25 miles. Then after awhile my front brakes will start to stick. All I have to do is unplug the vacuum of the booster and its fixed instantly. It's just like letting off the emergency brake. Now I may drive for 1 mile longer but as soon as I touch my petal they will start to stick. Each time I hit the petal they just get tighter until my rotors are cooking and my truck hardly had the power to roll. And then once again I unplug vacuum and boom it's fixed. This is why I'm stumped.

ksti

Did you replace the check valve on booster?

JonnyBoy

What happens if you plug the vacuum line and leave it off the booster? You won't have power brakes, but if you're careful you could do it with little traffic around as a diagnostic run.

Toyota~Boy

iTrader: (2)

As long as it is unplugged I'm fine. Trust me I done did that. Brakes are stiff as hell but it works.

I'm completely clueless on this guys. There's no possible way that I have a faulty booster or master cylinder. I bought a brand new booster prior to doing the booster swap thinking my old booster was bad. I still had the problem. So I know it's not the booster. Same for the master cylinder. I still have the new ones that I bought sitting here at my house.

Some of you all mentioned booster linkage. Is this were the rod connects to the pedal. I am aware of that and I understand that it has a adjusting nut on it just like the clutch. Could that really be my problem. Is there a certain spot that its suppose to be set at. I do know that I have just a little pedal slack when I hit my brakes. Pedal may drop 1/4 to 1/2 inch before I really got brakes. Now when my brakes act up I have absolutely no pedal drop. It's 100% solid kinda like it may be shoving up on my pedal.

JonnyBoy

Right, your booster isn't bad, I was just wondering if it did it with no vacuum to it. Without the vacuum, and therefore the booster to help your braking power, it's not doing it, therefore it sounds like your rod needs to be adjusted. Something or another is applying your brakes, whether you want it to or not.