Restore of my 1986 Bronco XLT

[Gary Lewis]

We aren’t as close as we were. Flew into Zurich and have worked our way down to Lugano now. Headed back north today and then west towards Zermatt.

On the brake system, there’s no bleed screw I’m aware of on the master. You just put a small amount of air pressure on top of the fluid in the master and that pushes fluid through the lines and out the bleed screws on the wheel cylinders and calipers.

[ReneH]

Hi, last weekend I've changes my front breaks and also the wheel bearings and seals. I also have cleaned and painted the hubs.







While trying to uninstall the old rotors, I have found out that I need a special tool...



I had to build one...including an adapter to be able to use with a torque wrench...

So, the job is done. But I'm not sure if everything is working as it should. It still wobbles when breaking. Not when trying to stop...more when I press the pedal not to the floor. But also not when pressing it slightly...hard to describe...it's also possible that the rear breaks are the source.
I'll perform some tests within the next days...

[Littlebeefy]

That is a really janky homemade spindle nut socket. I can’t imagine that thing allows you to torque spindle nuts correctly. Don’t you have Amazon? Maybe I’m just spoiled…

[ArdWrknTrk]

Rene, it's VERY possible you warped your rotors and/or drums decending those mountain passes while riding the brakes to failure.

I don't imagine a spindle socket for a 37 year old American truck is readily available in Europe.
I think you've done well to adapt and overcome!  

I've never set a front spindle to a specified torque. Perhaps when seating a new bearing while turning the wheel, but then I back it off to some minimal play (to account for heat) and call it good.

[ReneH]

Believe it or not...it works at 68nm without deforming...and yes, I can (and already have) bought the correct socket. But starting on the weekend with changing the parts, I have had no chance to get such a socket within some hours...

[ReneH]

I'm with you. But everything is new now. Rotors, drums, pads...

I used the torque wrench like described in the shop manual. Tighten to 68nm while turning the rotor and turned back about 45 degrees.

I have to check if the wobbling comes from front or back. My plan is to check if the wobbling comes up when pressing the parking brake step by step...

[ArdWrknTrk]

Seems a reasonable plan.

I hope you find the cause without much difficulty.

[ReneH]

There is something unusual I mentioned as unpacking the kit for the drum breaks...
There were two different shoes. Two had a thinner pad and two a thicker pad...is this common?

[ArdWrknTrk]

There's definitely a leading and a trailing shoe.
I always see the friction material is longer on one.
Never noticed that either shoe is thicker. That doesn't make sense....
Both use the same pivot and the drum is one inside diameter for both.

The one at the rear (coming from the adjuster to the top pivot when the vehicle is in forward motion) cams it self harder.
You have to pay close attention which you're installing the metal tab that the adjuster cable runs around.
Short friction always goes to the front.

Note the distance from top pivot to the beginning of the friction material in this photo from Akebono.

"Duo servo type drum brake:
The duo servo type features a structure where two brake shoes, called the primary shoe and secondary shoe, are linked via an adjuster.Strong pressure from the servo effect (self-boosting effect) of the primary shoe is transmitted to the linked secondary shoe, thus generated a very large braking force."

[ReneH]

Hmm...ok so it seems to be more uncommon...

I have mounted the thicker one to the back, connected to the parking brake cable.


Left side is thicker...I hope you can see it...

[ArdWrknTrk]

I can see your photo, but I don't understand it.
The pads should all be finished to a single arc matching nominal drum diameter.

Having short friction at the top of the front shoe is intrinsic to how servo brakes function.
That shoe needs to shift forward off the pivot when pushed by the wheel cylinder.
Brake shoes should come as two pairs.

[ReneH]

Ok...it looks exactly like before the change...only that the parts are new...

Yes, they are packed as pairs. One thick and one thin...

I have got 320 kN at the test bench...

[ReneH]

So as my rear breaks are jerking, I've take a closer look today. What should I say...the shoes are not the real problem. The problem was myself and also the drums!

First, I have mounted the shoes in the wrong way. The rear pad is the thinner one.
Yes, it's true! The pads having not only a different length, they're also differnt in thickness.
I have changed it!

While starting to re-mount the drums, I've noticed, that the drums don't center on the hubs...
By searching and measuring the inner diameter, I've found out that there are two differnt inner diameters are available!

3.44" (that's what I've bought)
2.87" (that's what I need!)
The most manufacturers even don't show this diameter in their technical description. So I only found the DURAGO BD8951 that will fit.

As currently needing the Bronco for driving to work, I have searched a way to center the wrong drums.
Here is how I've fixed it:



The drums aren't jerking anymore. And also the deep sound while driving isn't there anymore. The interesting thing is, that also the former owner has mounted the wrong drums...so I have had any suspect while mounting the new ones...

I've orderes the correct drums now...what a journey!

 

[Gary Lewis]

Wow!  That's a good find, and should make a huge difference.

How did you center the brake drum?  It looks like you used some kind of sleeves to secure the drum and probably spun the axle and played with it until it looked like you had it centered.  Then put the wheel on and cinch the nuts down.  Right?

[ReneH]

Yes, I've used a pipe that had the correct outer diameter to fit inside the holes of the drum. I drilled the pipe, after cutting three pieces of it to the correct inner diameter to fit over the wheel bolts. I used three of it to get the drum centered as best as possible.

But this is not a real solution. I will oder the correct drums form rockauto.com for my hubs.

I also have to add the turn signal switch, cause the one I've already got was also wrong...I've a tilt able steering wheel (what I've not known before) and ordered a switch for a non-tilt able one...

[ReneH]

I've reclaimed the missing description at rockauto.com. only two drums tells the size of the hub hole...I've got the wrong one for my hub...



This one with a hub hole diameter of 2.87" will fit to my hub:


I hope rockauto.com will send my money back. My way to center the wrong drums is more amateur than professional.

[Gary Lewis]

Hope they send the money back.  But in any event you are on the right track.  

[ReneH]

Thanks Gary.

But do you think I can stay with the current, wrong drums?

Not only the hub hole differs...also the size of the break surface is 0.1" larger at the correct drums...and the height differs...

I can turn an adapter plate...but I don't know if this is the right way...

[Gary Lewis]

On something as critical as brakes, and on a vehicle you've spent a lot of money on getting "right", I wouldn't mess around with adapters.  Get the right drums.

[ReneH]

Today is a good day. Rockauto.com has answered. As they are writing in German, I've used Google translator:

"Good day,

 We're sorry you're having a problem with your order.  You have discovered an error in our catalog.  Since the problem is our fault, we would like to offer you a full refund for the cost of the goods and associated shipping costs.

 We will update our catalogs for this drum set, thanks to your help.

 We will issue a refund without a return within the next 3 business days.  We will email you once the refund has been issued.

 We apologize for the inconvenience."