Soft pedal, suspect master cylinder...

[hotwings]

Hey guys,

I saw a few threads that sound like a similiar problem I'm having but just want to confirm.

have 83 FJ60 that does have 2 vaccume hoses plugged, I orderd the emmissions control FSM and will tackle that when the book gets in... I don't think my brake issue is related but appreciate your opinions.

Scenero:
Turn truck on for first time in morning. pull out and take off and when I press the brake pedal to stop for the first time the pedal goes down probably 2-3 inches. I pump the brake and the pedal is firm. drive down the street for a min or so and hit brakes again, pedal still firm. get on high way for while then take my exit pedal is soft again but not as soft as morning, maybe 1-2 inches. the longer In constant stop and go the pedal is firm, it is after long intervals that the pedal is soft, at least that is how it has been the last week.

bought the truck about 3-4 weeks ago where it was driven maybe once a week or so, not often. Now it is a daily driver, about 60 mi or so a day. The pedal was solid when I first bought it but after a couple of weeks it is doing this.

The issue started after my way back home from my 3rd wheeling trip in it.

Fluid level is still high and have not noticed any leaks. After pedal has been pumped, it brakes well so I feel the booster is ok (hope, that thing is expensive). my suspision is the master cylinder has bad inner seal but wanted to see if anyone could confirm.

Parking brake works, is very firm at like 5-7 clicks or so. brakes are smooth, not bumpy.

sorry so long but I wanted to be descriptive. thanks in advance

 

[Toadhopper]

Hard to say exactly, but I would flush out the fluid to get the old crap (and maybe air) out.
If you haven't adjusted the e brake up front, then the rears are prolly not out of adjustment (if they're working), but thats another place to check. I'm not saying it ISNT your MC, but the fluid and rear adjusters are easy to do and cheap, so I'd start there.

 

[adidasprof]

I had the same issue with my FJ62. I had just done some brake work and thought maybe I didn't bleed them properly. So I rebled the brakes and still the same issue. I did this a couple of times with the same result. Finally ended up replacing master cylinder and all is well.

 

[hotwings]

For the rear adjusters, is that just spooning the gears out until the shoes touch the drum? I've never really been very good at doing drum brakes. I started thinking that that might be a possibility after I posted my problem. And after driving it today I actually counted 10 clicks until the hand brake actually holds on a slight incline.

and is there any reason the brakes would have air in them if they haven't been serviced in years and are not leaking? They were very strong for the first week or two after I bought it. It still has plenty of fluid in resivior and no brake light on instrument panel. But they did start messing up after my 3rd wheeling adventure, noting to crazy it is a completely stock FJ60 with probably all toyota parts as far as I can tell.

Also, Seems to be worse in morning when it is colder and not as warmed up.

 

[Jan-78FJ40]

For the rear adjusters, is that just spooning the gears out until the shoes touch the drum? I've never really been very good at doing drum brakes. I started thinking that that might be a possibility after I posted my problem. And after driving it today I actually counted 10 clicks until the hand brake actually holds on a slight incline.

and is there any reason the brakes would have air in them if they haven't been serviced in years and are not leaking? They were very strong for the first week or two after I bought it. It still has plenty of fluid in resivior and no brake light on instrument panel. But they did start messing up after my 3rd wheeling adventure, noting to crazy it is a completely stock FJ60 with probably all toyota parts as far as I can tell.

Also, Seems to be worse in morning when it is colder and not as warmed up.

there should be no air, no matter how long you drive it. the brake system is a closed system.
Did it improve with adjusting the rears correctly?

Also, make sure your wheel bearings are tight. If they are only slightly lose, the brake disk will push the brake cylinder apart, and you need more travel to get a firm pedal. just lift the wheel and wiggle it, it should be completely tight.

 

[wengejor]

I recently had to replace a section of hard line along the frame. It was rusty at one of the hangers that holds it to the frame. There was a small hole where it was leaking and I ran my finger over it and a flake of rust came off. Got back in the truck and the pedal went to the floor and it was then gushing fluid.

A-zone has long lengths of brake line that you can get along with a crimp tool to make your own ends and fittings.

 

[jmylie]

Rear brakes are a pain, that is where most of the issues come from.

I'm guessing that they need to be adjusted and your self adjusters are most likely not working. They tend to freeze up.

Pull the rear wheels and inspect the adjusters, they should move by hand and the rear brake shoes.

The adjusters, are the levers on the back of the rear brake drums where the parking brake cable attaches

I would manually adjust the rear brakes (spooning? out the gears) assuming the shoes are ok.

Use a brake tool or a flat bladed screw driver to adjust the brakes. The brake pads should "lock" the wheel and then back off a few clicks. The brake should not drag.

If that does not do it, you may have a M/C problem.

 

[hotwings]

Thanks for all the replies and advise.

Well it turns out that it was the front brake pads that needed replacing as well as the hub seals. With the combination of the bad hub seals and the very low pads it required the pistons on the calipers to over extend and required additional pumps of the pedal to make pad/ rotor contact.

The seals were toast and there was a bunch of liquidy junk in the hub. got to it in time though and the brakes are firm and it stops great now.