My front disk brakes are dragging! (1 Viewer)

[BladeRunner80]

Hey all,

Well, last summer I changed out my front brakes and replaced the drivers side caliper. I noticed that after driving (usually not very far 5-10 miles) that my front brakes were dragging (I pulled the tire off and the wheel did not turn very freely). A fellow cruiserhead said I should replace the caliper since it was probably shot, so I did and replaced the the pads on both sides.

Well, fast forward to today (the truck has been sitting in my garage since just since last summer and I just started driving it again last month) and I decided to jack up the truck and check the front brakes. This was after driving for a little while and its doing it again. Who knows, I may not have even fixed it right last summer and didn't drive it enough to notice.

What should I do to get these brakes working right again? Do I need to bleed them more? Any help would be much appreciated.

Oh, I did check the rear wheels for good measure and they spin freely. I have rear drum and front disk.

Thanks!

 

[Bossman]

Need a little more info. Is it the 67 in your sig line? If so, what conversion did you use? What master cyl did you use? Did you remove the residual valve if using a drum/drum master? Help us help you...

 

[Pin_Head]

All disk brakes drag, so it depends on whether it is too much. If the brakes smoke or you can't hold your hand on the hub after driving 5-10 miles then it is too much.

 

[dgangle]

Consider adjusting the pushrod length in the brake booster. Did you renely change either the booster or MC?

 

[1 Bad FN FJ]

Car Craft magazine had an article about this issue, pertaining to the portioning valve for drum brakes being different then for disc brakes. What master cyclinder are you using? I went with the new Chevy power brake unit from BTB in Henderson Nev. when my old stock power brake unit took a dive. Decided to upgrade everything when I put disc on the rear. It comes with a portioning valve and everything you need for $4oo. Quite happy with the way it stops now. Follow your lines from the master cylinder line down to see if it runs into a valve , you may need to eliminate it.

 

[BladeRunner80]

The front disk conversion was done by using a front end off a newer FJ40. Must be from at least a 75' since that was the first year for disk. I looked at SOR to identify which master cylinder I have, it is a dual resovoir set-up, looks to be the one they started using in 75 as well (one large and one small resovoir) with a large brake booster behind it. I am unsure what a reisdual valve is, something for drum brakes?

The wheel hub seemed hot, but I could hold my hand on it without any problems. Also, there isn't any smoking and I can't smell any burning. Am I just overreacting here? There also doesn't seem to be a whole lot of brake dust, so I doubt its eating the pads up real quick.

Thanks everyone!

 

[steverb]

When you take the calaper off dose the cilinder push back easly with a c clamp. If not you rubber brake line could be collapsed and not alow the pressure to return to the master.

 

[BladeRunner80]

I read the "how to" in the technical links section on removing the residual valve. I'm a little confused, so here is my question.

I want to leave the reisidual valve in for the drum brakes correct? So I would remove the line for the front brakes, check for the valve, replace the line and bleed the brakes?

 

[Poser]

I want to leave the reisidual valve in for the drum brakes correct? So I would remove the line for the front brakes, check for the valve, replace the line and bleed the brakes?

That is it.

 

[BladeRunner80]

Thanks for all the tips. I did a lot of drivng in the crusier last night (still making sure everything cool correctly). Anyhow, I got home and the hubs were barely warm, calipers were pretty cool to the touch, I didn't touch the rotors.

Oh well, I'm going to take it on a semi-long day trip on Saturday, we'll see how they hold up.



P.S. - Thanks Poser!

 

[plaiii]

A little food for thought in case the problem arises again. My '76 FJ40 developed a problem with the front passanger caliper. Shortly after I bought it I noticed the brakes seemed to be touchy. At first I presumed this to be Cruiser characteristics as I was new to them. Several weeks later it suddenly veered to the right and kept pulling that way. The rim was too hot to touch and there was brake dust all over it. This just happened out of the blue. The problem was in the caliper. The pistons were seizing in the applied position. I don't know about the '75 caliper but the '76 has four pistons per side. each piston has an o-ring. In my case, age, heat, and crud in the caliper assembly had contrived to "gum up" the works. It took some doing to remove all four pistons ( I ruined two of them). I soaked the caliper assembly and used Scotchbright to polish the piston cylinders. I reassembled with all new o-rings and seals ( and two new pistons). No problems since.

Leon...

 

[zuluzeugma]

agreed. If the rubber boots around the pistons fall apart water gets in there and rusts the pistons to the cyls. I rebuilt both front calipers on my fj60 for that exact reason. seams strange that you would have that kind of faliure for only a year old caliper though. Was it remanufactured?

 

[BladeRunner80]

I noticed this on both front brakes. One of the calipers I just replaced last summer. Since the brake job, the truck has probably only seen 50-60 miles. I'll watch this weeknd and see how it goes.

Thanks!

 

[Fast Eddy]

I want to leave the reisidual valve in for the drum brakes correct? So I would remove the line for the front brakes, check for the valve, replace the line and bleed the brakes?

Please confirm that you bought a new Toyota '75-'78 master cylinder and it came with residual valves in both circuits. I keep saying this. I've got two that came like this before I figured it out.

 

[BladeRunner80]

I know I started this thread almost two months ago......but I finally got around to pulling the brake line and snapped it in the process!

Anyhow, Fast Eddy: There was a residual valve in the front brake line circuit, which seems odd because the M.C. is from a newer FJ40 (it is a dual resevoir with the lines running out the top, not the sides). I didn't pull the rear circuit apart.

I'll report once I get the front lines fixed (hoping to dig into it tonight) and let you know if it fixed it. Although, it seems odd that there would be a residual valve in there if they aren't needed for front disk.