Brake help 1968 Bronco

[KDAWG97M3]

I need some help! I have a 68 bronco. The brakes are hard. I have replaced the master cylinder, two rear lines, two front wheel cylinders and the two lines from the master cylinder to the proportion vale. I have bled the brakes, but not much comes out. Is this due to the prop valve? How do I “open” it to bleed? Also my red brake light is on my dash now. Never had that before. Any help would be appreciated

Also the truck is still drums- I have considered the disc swap, but want to keep my truck original. Maybe I am being shortsighted, I don’t know.

Thanks for your help in advance!

 

[DirtDonk]

If you drive the truck more than occasionally and more than around the block, and if you don’t want to spend once a month readjusting the brakes to perfection, then screw original!
Disc brakes are probably still a single most important/best change that you could make to an Early Bronco.
As for original, nothing you do to convert to disc brakes is permanent. It can easily be converted back to original if you decide to build a show truck. Or have some original special version that has more value the more original it is.
But while you’re driving it, run disc brakes.

Now on to your issue.
Do you have a power booster on there?
Original master cylinder and line routing?
And post up a picture of your “proportioning“ valve, in case it’s just the standard H block.
Sounds like it’s still original, so there would be no reason for having a proportioning/combination valve installed.
Originally it would have been an H-shaped distribution block with the brake warning lamp switch in it.
Assuming, of course, that you’re 68 had a dual master cylinder. Which I think all 68 had, but if early enough, you never know.

 

[bmbm]

Definitely disc. I have all my original brake parts stored in the garage.

 

[KDAWG97M3]

thanks

 

[nutter3]

4 wheel drums with power assist can stop very well. They are a pain to keep adjusted. Water crossings suck with front drum.
If yours are hard and not much fluid coming out, you have a blockage somewhere. do the rear brakes bleed? I would guess if the red lamp is on, you have flow to either front or rear, but not the other.

 

[KDAWG97M3]

If you drive the truck more than occasionally and more than around the block, and if you don’t want to spend once a month readjusting the brakes to perfection, then screw original!
Disc brakes are probably still a single most important/best change that you could make to an Early Bronco.
As for original, nothing you do to convert to disc brakes is permanent. It can easily be converted back to original if you decide to build a show truck. Or have some original special version that has more value the more original it is.
But while you’re driving it, run disc brakes.

Now on to your issue.
Do you have a power booster on there?
Original master cylinder and line routing?
And post up a picture of your “proportioning“ valve, in case it’s just the standard H block.
Sounds like it’s still original, so there would be no reason for having a proportioning/combination valve installed.
Originally it would have been an H-shaped distribution block with the brake warning lamp switch in it.
Assuming, of course, that you’re 68 had a dual master cylinder. Which I think all 68 had, but if early enough, you never know.

I am probably going to take your advice but in the meantime

Do you have a power booster on there? NO
Original master cylinder and line routing? New MC original line routing yes
And post up a picture of your “proportioning“ valve, in case it’s just the standard H block. I think it is. Yes.
Sounds like it’s still original, so there would be no reason for having a proportioning/combination valve installed.
Originally it would have been an H-shaped distribution block with the brake warning lamp switch in it. Yes that is the one I have
Assuming, of course, that you’re 68 had a dual master cylinder. Which I think all 68 had, but if early enough, you never know. Not sure what you mean by dual MC. Can you explain?

Thank you very much for your help

 

[DirtDonk]

Usually referred to as a “tandem” master cylinder, I believe, I simply meant a master cylinder with two reservoirs.
One for the front brakes and one for the rear.
Previous iterations, especially on the 66, and I think 67, had a single reservoir master cylinder.

 

[Broncobowsher]

'68 never had power brakes, wasn't even an option. Manual (non-power assisted) Bronco brakes have always been heavy. That is how all of mine have been. If all you have ever driven is power brakes, yes they will feel very heavy.
On top of that, how tall of a tire are you running? That is added leverage on the brakes. Making them work harder, and heavier in the pedal.
Disk brakes won't magicly make for a a lighter pedal. There are plenty of other benefits, but they won't feel like power brakes.

Broncos work really good with hydroboost form of brake booster. Vacuum brake boosters were a factory option at the end. The factory version uses a different driver's inner fender for clearance. Aftermarket gets around this. But the factory vacuum boosters are a bit small. Generally have decent power assist at light to moderate braking. Often run out of assist on a hard stop. If you have power steering, or even have plans for power steering, just skip the vacuum booster and go straight to the hydroboost. Plenty of people have gone from vacuum boosters to hydroboost. Never heard of anyone pulling a hydroboost and putting a vacuum booster in.

 

[bmbm]

I need some help! I have a 68 bronco. The brakes are hard. I have replaced the master cylinder, two rear lines, two front wheel cylinders and the two lines from the master cylinder to the proportion vale. I have bled the brakes, but not much comes out. Is this due to the prop valve? How do I “open” it to bleed? Also my red brake light is on my dash now. Never had that before. Any help would be appreciated

Also the truck is still drums- I have considered the disc swap, but want to keep my truck original. Maybe I am being shortsighted, I don’t know.

Thanks for your help in advance!

If your brake warning light came on after you worked on the brakes there is likely a problem with what you changed. Many replacement parts such as master cylinders and wheel cylinders are china made now and often of poor quality and/or not original manufacturer specs. Wheel cylinders can often be rebuilt so hang on to the originals just in case.
It has been a long time ago but when my 1966 had the single reservoir master cylinder, 235 75 tires and drums in front I don't recall the brakes being hard for non power assisted brakes but I drove vehicles with manual brakes for years.
I did the typical GM front disc conversion and noticed a bit more force needed to stop but had the power assist in mind anyway and will not have larger than 31" tires on this Bronco so at least for my use it will not need hydroboost.

 

[SLOWnEASY]

First thing I would do is to open each bleeder and have an assistant press gently down on the brakes until the pedal hits the floor. Then have them hold the pedal down while you tighten up the bleed screw. You should see a good stream of brake fluid come out each wheel cylinder.

When I have trouble bleeding brakes I go to using my finger tip as a valve on the bleed screw.
Put on a nitrile glove. open a bleeder and plug the end with my finger.
Have someone press down the brake pedal while I angle the pressure on my finger tip to direct the fluid away from me. Press your finger up tight to stop the air from coming back in while the assistant lifts their foot.
Refill the master cylinder after every three cycles.
After you get good flow out a wheel cylinder do one last normal bleed before you move to the next cylinder. (bleed screw tight, helper puts pressure on pedal, open bleed screw to let pressure out, tighten bleed screw when the pedal drops to the floor).

Brake fluid is water soluble so get out the garden hose and wash it the underside of everything when finished.

 

[DirtDonk]

Don’t know why I didn’t jump on the same bandwagon. You need to describe “hard” to us. Do the brakes actually stop the vehicle?
Is the pedal overly firm?
What size tires?
Have you ever driven a manual break older truck before?
Those are all important aspects to this discussion.

 

[bmbm]

If your brake warning light came on after you worked on the brakes there is likely a problem with what you changed. Many replacement parts such as master cylinders and wheel cylinders are china made now and often of poor quality and/or not original manufacturer specs. Wheel cylinders can often be rebuilt so hang on to the originals just in case.
It has been a long time ago but when my 1966 had the single reservoir master cylinder, 235 75 tires and drums in front I don't recall the brakes being hard for non power assisted brakes but I drove vehicles with manual brakes for years.
I did the typical GM front disc conversion and noticed a bit more force needed to stop but had the power assist in mind anyway and will not have larger than 31" tires on this Bronco so at least for my use it will not need hydroboost.

Also if you decide to rebuild the drums I would be tempted to leave the original brake hardware, springs etc in place if they are in good condition. Much of the china made stuff is poor quality and/or not manufactured to original oem specs.

 

[B RON CO]

Hi, a properly assembled and adjusted drum brake set up will be hard when you step on the brake pedal. When the shoes wear, the pedal goes down, and you may have to pump the pedal to activate the brakes. Unless you inspect each brake assembly, and know what it is supposed to look like, there may be issues. The common issues, besides worn linings, are brake shoes installed in the wrong position, and leaking or rusted wheel cylinders. If you remove the drums, post a picture of each wheel, and the guys will see if it looks good or bad. That is also the time to pack the front wheel bearings. Good luck

 

[Broncobowsher]

If you go and pull the front drums, it is a lot more work than the rears. the rears (should) just slide off after the rear wheels are removed. Make sure you don't have the park brake set when trying to remove them. The fronts (if correct) have the drum and hub as one piece. to get the drum off you have to take apart the lockout and there is a special 4WD socket for the nuts on the front wheel bearings. Once the nuts are off the outer bearing can come out as you pull the hub and drum combo. Wear lips on the drums can make extra work as you have to back off the adjusters to shrink the shoes down enough for the lip on the drum to pass.