Rear brake/hub issue

[whtbronco]

I went to adjust the parking brake on my 04, the parking brake on these is as many have found the most frustrating and challenging brake assembly I have ever deal with. Drum brakes are no problem for me, these are special. I found that my rear rotors were not running true, like they had warped both side-side and up-down causing the parking to rub every rotation. You could see the rotors move in/out a little and up/down much more about 1/32" with the rear on jack stands, removed tires/wheels, engine running and in gear. Okay so I checked the hubs, these were running slightly out of round as well. At least this makes sense since it's unlikely both rotors were messed up and just how the hell does a rotor get out of round in circumference anyway. I also talked to my wife since she had recently jumped a local railroad track about how high she went, 2' give or take she said, ugh. I replaced the hubs, the hubs ran true, but the rotors had no improvement. Fine I'll replace the rotors, and the pads and parking brake as well. Same results. I'm completely lost as to how this is possible and what to do. The only other thing that rotates are the cv axles which are fairly new Motorcraft brand. Any thoughts on what to do?

Hubs replaced with Motorcraft. I tried SKF and returned them as they were not what I wanted, they did not match the photos and had the same part # printed on them as Moog's.

Rotors Raybestos truck specialty high carbon, figured I'd try them since I like their pads so much. Pads because I love these pads the Raybestos Element3 Hybrid, GG rating and man they bite great and provide wonderful feedback.

 

[Hamfisted]

Are you adjusting your parking brake with a caliper? Or just doing it by feel / ear ?
Normally they're adjusted when installed new with a caliper.
The diameter clearance is .010" - .012" between the shoe surface and the drum of the rotor.

12" Digital Caliper on Amazon







.

 

[whtbronco]

Yeah this time I decided to do it right and purchased a drum brake gauge, GearWrench 3377. In hindsight I think a traditional 12" long reach digital caliper would have been easier. The drum gauge certainly made setting the parking brake easier than doing it by feel which I think is questionable at best, but still far more time and effort than I have ever spent on full size drums.

With the hubs and brakes I replaced still on it I had backed the parking brake adjuster off all the way and then removed it entirely. That made it rub just a little bit so I could drive it, though being someone that uses the parking brake every time I park I sure didn't like it.

Anyway, I cannot wrap my head around what's causing the rotors to run out of true. I even cleaned the spindle and and dust shield to ensure I didn't have any crap get in between. I think I'm gonna take the rotors to a local machine shop and have them checked.

I've got until next Saturday to resolve this and a control arm bolt/nut replaced since it won't stay tight. Kinda feeling the pressure. My daughter is going back to college and being in ROTC she has a lot of gear to haul.

 

[whtbronco]

Since no one likes a thread with no resolution here's a quick update.

I found a Ford/Motorcraft control arm bolt that I thought would work and it did. The nut was a bit small in total diameter so I picked up a grade 8 washer as well. The bolt now tightens and I was able to throw it through turns again consistently. The local Ford dealer said I needed a $135 cam kit that had to be ordered. They had the nut and bolt in stock though.

Nut: W520217-S441 $2 ea
Bolt: W712104-S439 $12 ea

On to the hubs and brakes. A 2nd set of new rotors are expected to be delivered tomorrow. Motorcraft this time. I'm quickly realizing that for most things I am much happier if I buy genuine GM and/or Motorcraft parts.

Interesting thing. We have 2 GM W-body Monte Carlo's, the Expedition and a Ranger. The Ranger is the only one with drum rear brakes, it also has by far the best parking brake of the 4. Course it uses the full brake shoes with vastly more surface area than the others as well. Drum brakes aren't all bad, but the hat style rotor with mini-drum parking brake just sucks.

 

[whtbronco]

I really like the Raybestos Element3 Hybrid brake pads. They are rated GG, stop great and provide terrific feed back. That said I won't buy another Raybestos rotor. After 2 sets were significantly out of round. The Motorcraft rotors are near perfectly round as they should be.

So the very minor vibration from 65mph and up is now gone, had no idea it was the rear hubs. The parking brake remains to be addressed. It's become clear to me that this rather simple process entirely escapes me. I have very carefully set the drum gauge tool and then used it to set the parking brake shoes. If I set the shoes to 0.02" under the drum size, the rotor won't even go on, I know that, makes no sense. It's very obvious that the brake shoes are not even close to producing a circle, the center of each is the widest point and is what contacts the drum. I have 3 sets of shoes on hand, the factory Motorcraft, Wagner and Raybestos. The shape of all 3 matches. The originals are worn only in the center of the shoes. For the moment the parking brake shoes are set to 0.06 smaller than the inside diameter of the rotor drum. Of course the parking brake is pretty much useless at the moment. These new Motorcraft rotors were fully coated I'll wear the coating off the drum surface today and try setting it again this weekend.

 

[whtbronco]

Took a while to get back to this, though interestingly the parking brake improved slowly during this delay. I use the parking brake every single time I park. I think these parking brake shoes flex when applied and begin to flex a bit easier over time, anyway that's my thought.

I intentionally lightly and for short distances applied the parking brake multiple while driving slowly times to fully wear the coating off the braking surface and wear the center of the brake shoes. This likely contributed to the improved performance.

I have now been able to set the parking to just 0.04" smaller than the parking brake drum inner diameter. That's as close as I can get right now without requiring too much effort to install and rubbing too much when not applied. It's good enough now and holds quite well considering it's a truly pathetic design. Traditional drum brakes or a caliper with the parking brake integrated would be vastly better.

I may revisit this again in the future to see if I can get closer to the recommended 0.02" gap, but I'm not sure the performance would improve any.

In the end the fix was new hubs and rotors(3rd set were round) which required new pads and I went ahead and replaced the parking shoes again, though I'm not sure that was needed. I always replace all the brake hardware so I did that as well, there's no increase in effort and it's low cost.

 

[Vincent Vega]

@whtbronco thanks for the info on this. I am a Motorcraft guy but recently caught myself looking at cheaper rotors to replace my rear brakes soon. Your posting helped set me straight again. BTW I don't think my parking brake has worked worth a Sh since I bought it new in 04.

 

[whtbronco]

I'm always trying to save a buck as well, but the last couple years it seems I'm not pleased with most parts that are not factory replacements. I hate the price, but sometimes it's worth it.

Here's the rear brake parts I used from Rock Auto:
Rotors: MOTORCRAFT NBRR109 (Fully Coated (Maximum Protection For Rust Prone Areas)) Service Design; Coated $51 (these rotors still look new due to the lack of rust)

Pads: RAYBESTOS EHT935 (Premium) Element3 Hybrid Technology $34 (love these pads)

Parking brake shoes: RAYBESTOS 811PG (Daily Driver) Organic $12

Caliper pins: RAYBESTOS H5025W $2 (turns out they were likely not needed)

Parking brake hardware: RAYBESTOS H7325 $22

 

[whtbronco]

I also used a brake shoe caliper like this one:

https://www.amazon.com/Westward-1EKA5-Brake-Resetting-Gauge/dp/B001GIUCSK/ref=sr_1_16_mod_primary_new?crid=1NDXXHYNXH4ZX&keywords=brake+pad+measuring+caliper&qid=1677631965&sbo=RZvfv%2F%2FHxDF%2BO5021pAnSA%3D%3D&sprefix=brake+pad+measuring+caliper%2Caps%2C85&sr=8-16

That said I had pondered just getting a set of digital calipers with longer arms and in hindsight I wish I had. At least I'd be more likely to use it and I found the caliper I bought kinda tough to use. No matter what tool you use to measure the drum and set the shoes make darn sure you measure and "do it right". Otherwise it's a crap shoot at best, 1 side will work better than the other and you will fight for hours or more trying to get it right.

Something like one, that's a bit expensive, just make sure it will measure inside and outside and locks:

https://www.amazon.com/Mxmoonfree-Calipers-Measuring-All-metal-Resolution/dp/B08YK3P6P8/ref=sr_1_3?keywords=long+arm+digital+caliper&qid=1677632206&sprefix=long+arm+digi%2Caps%2C93&sr=8-3&ufe=app_do%3Aamzn1.fos.08f69ac3-fd3d-4b88-bca2-8997e41410bb

 

[Randy-IA]

What you describe with your parking brake is why I left all the guts out the last time I put new rotors on.

What you can do is harder to accomplish but works very well in most cases. Just add in a line lock. It's not cheap or easy but it uses the caliper as the brake. Assuming you can find a unit that will hold pressure indefinitely. I have no suggestions for that.