'93 E350 Motorhome - really frustrating brake problem

[rgnprof]

I have been chasing this issue - literally - for years. I have a "93 Ford E350 Motorhome with front disc and rear drum brakes (RABS). I have had a very spongy, soft pedal and I'm almost positive I've been stopping this coach with only the front brakes. Recently pulled the rear duallys and changed out everything - new drums, hardware, wheel cylinders, shoes...

And I still have the same issue. Today, I've pulled the rear wheels again trying to adjust the brakes. I have spent several hours trying to get them adjusted but I still have no real brake in the rear wheels to speak of. My wife was in the coach, pressing the brakes and I was still able to turn the drums by hand (no tires installed yet) with the brake pedal depressed.

Also, I changed out the master cylinder last year and I have bled the **** out of these brakes!

Any thoughts? My only thought is I still have a hydraulic problem - although the front disc brakes seem to work, OR I still have not gotten these rear shoes adjusted properly to the drums.

Please help! Thanks!
ryan

[ron_dittmer]

fourthclassC wrote:
Howdy,
I also want to suggest/inform that the automatic brake adjusters (almost never work, I know) are supposed to tighten when backing up and applying the parking brake - not the service brake. I add this for additional information, not resolution of OP's issue.

We all agree that in a perfect world they will self-adjust. But as the brake system ages with corrosion and crud, they quickly loose the ability to self-adjust. And in the case with the original poster, his rig is now 23 years old. I wouldn't count on any kind of self-adjusting. In fact, every E-series cut-away with drum brakes are all very old today. Those owners should not rely on the self-adjusters. Adding the point that just about every motor home is stored outdoors with humidity encouraging corrosion, that further contributes to self-adjustment failure.

I think it is best to do it manually one real good time like I described in the beginning of this thread, and maybe adjust once in a while as you feel needed.

[fourthclassC]

Howdy,
I also want to suggest/inform that the automatic brake adjusters (almost never work, I know) are supposed to tighten when backing up and applying the parking brake - not the service brake. I add this for additional information, not resolution of OP's issue.

[Bordercollie]

I have a old Indian motorcycle and remember that after the drums were machined out on a lathe, the new shoes were shaped on a machine that sanded the shoes to match the arc of the drums. If this was not done, the new shoes would not contact the drum evenly and brakes would be ineffective until they wore into the same arc as the drum. If the shoes do not match the drums, adjusting may make the brakes drag but they won't be effective. (At least this is as I remember drum brake technology.

[ron_dittmer]

Bummer that you can't adjust them looser without taking off the wheels. Hopefully you will get a good "feel", how tight is not too tight, but rather just right.

You do understand that in order to back off the brake shoes, you have to push in the lever with another screw driver to unlock the teethed wheel, right?

You need to work with 2 screw drivers inside that little slot, one to push in the lever a little, the other to turn the teethed wheel in the loosening rotation. As soon as you release the lever, it pushes right back against the teethed wheel and keeps it from turning in the loosening direction.

ADDING: Just a reminder that when quickly backing off on the tightness, your old 1993 E350 parking brake should NOT be set for it might make it extremely difficult to back it off. I believe the older E450s have the parking brake located on the drive shaft so that suggestion would not apply.

[rgnprof]

Yes, the rear left (Driver's side) was way too hot to touch - that's why I backed it off...

I'm probably not in to spending the money to upgrade the brakes at this point (on a '93)...and, it's stopped me fine - just have to pay attention and be careful to not let things up front get too hot. I will probably keep at adjusting the rears, problem with this is that it's difficult to back them off if I overtighten them - I usually have to remove the wheels to do it, because I am having a hard time moving the adjuster "back"...

[j-d]

Ron's statement about 200SEVEN E-Series is correct, but Ford made a huge change in 2008. In that year, they ENLARGED the Front Disc Brakes substantially, and used the same Axle and Brakes from E150 all the way through E450. Several of us have bought new components, removed by shops that convert E-Series to 4x4.

CarringB and Holiday27 got their parts from QuadVan in Oregon

j-d and Deprived got ours from Quigley. Mine came from PA, I think Quigley sent Deprived's from Texas.

Installing late model front brakes (buy the whole axles if your ball joints are wearing out) won't solve the rear brake issue, but it will give you WAY more stopping power from the front brakes, and far less fade.

I don't have a spec for brake temps. I know that if a caliper locks up, THAT brake is like walking up to a BBQ grill.

[ron_dittmer]

I would be concerned only if the hubs were too hot to touch. Were they that hot? If so, which ones?

[rgnprof]

I have a laser thermometer - anyone have any idea of acceptable/excessive temps for front disc rotors and rear brake drums? They were hot - not just smelling hot...

[ron_dittmer]

rgnprof wrote:
We started off for Colorado and I noticed the back left dually tires smelling and getting hot - so I decided to back it off some before we left. I probably loosened it too much, I don't know...they braked alright on our trip - maybe better than it has in the 6 years I have owned the coach, but pedal is still spongy...and front brakes got really hot once - coming down from Bobcat Pass in New Mexico. I am sure I'm still 'overusing' the front brakes...

ryan

Very interesting.

First, please understand that I am not an expert on this, but...

That pad-burning smell could be the pad material wearing to conform to the drum properly. Was it hot to the touch, or just that burnt brake pad smell?

If I were you, I would tighten them up as we discussed earlier and take short trips driving around town to work, shopping, church, etc. and let the temperature-to-the-touch on the hub determine if you over-tightened the rear drums. If all your brakes are working together, the rear hub temperature should feel a little less warm than the fronts. If they are initially warmer but not too hot to touch, I would continue to drive locally and see if it changes to give the rear brake shoes some time to wear and seat properly. If you have wheel covers, take them off so you can touch the hubs directly.

The automotive industry states that brakes on cars, the fronts do 2/3 of the braking, and the rears do 1/3. I would think that a motor home with 2/3 to 3/4 of the weight sitting on the dual rear wheel axle, the ratio could be 50/50 or even flipped.

I have in front of me the 2007 Ford specs on the E-series, covering the E150 all the way to the E450-stripped chassis. The E150 has smaller brake parts which is understandable. But the E250 van all the way up to the E450 cut-away and stripped chassis use the exact same rotors and calipers. As with the shock absorbers and stabilizer bars and such, Ford uses critical safety E250 (GVWR 8900) van parts on an E450 (GVWR 14050) that carries 5150 pounds more weight. What does that indicate? Not so good a feeling for me. That explains why I had to upgrade my stabilizer bars, shocks, and steering damper.

I am not suggesting to upgrade your brakes to heavy duty aftermarket versions. Just get your rear drum brakes to do their share of the work.

I nearly killed me and my family in our rig with rear drum brakes that were not adjusted which had rendered them completely ineffective. On a trip in the mountains, braking in the turns, the fronts were doing 100% of the braking. The rig was pre-ABS so the fronts would on rare occasion lock up and skid while braking in the turn in the mountains with the cliffs right in front of me. What saved us was practicing so much engine braking. During that trip, the light bulb in my head went off about checking the adjustment of the rear brake shoes. When back home after adjusting and the break-in period had passed, the vehicle stopped on a dime for the remainder of our ownership which was over 10 years. I never touched the rear brakes again.

Ryan, I know you don't need convincing. I say this for the others reading this.

[rgnprof]

We started off for Colorado and I noticed the back left dually tires smelling and getting hot - so I decided to back it off some before we left. I probably loosened it too much, I don't know...they braked alright on our trip - maybe better than it has in the 6 years I have owned the coach, but pedal is still spongy...and front brakes got really hot once - coming down from Bobcat Pass in New Mexico. I am sure I'm still 'overusing' the front brakes...

ryan

[ron_dittmer]

rgnprof,

Do you have anything new to report on the adjusting of your rear drum brakes?

Ron

[SoCalDesertRid1]

After owning several Ford trucks with rear drum brakes, I am convinced that Ford cannot make a self adjusting drum brake system that is worth a carp.

On all my Fords, no matter how well the rear drum brakes were manually adjusted and working great, it only lasted for a while and they would be right back to being loose and the front brakes doing all the work. And I did alot of backing and braking with my trucks, which is how the adjusters are supposed to self-adjust.

In my experience, Ford rear drums require manual adjusting about 3 or 4 times on a heavily loaded truck (or motorhome) between a typical oil change interval, or you won't have any rear brakes.

I had never needed so much adjusting with my old Chevys or Dodges with rear drums.

[ron_dittmer]

rgnprof wrote:
Great help! Thank you gentlemen!

Something Ron said at the end of his post struck a note: We bought this motorhome from a some parents of friends of ours in 2010. The year before - maybe 2008 - the brakes went out on them in the Rockies. They took it to a brake shop in Estes Park and spent all kinds of money to get everything fixed. The PO discussed all of this with me and also stated that ever since then the brakes had been mushy/spongy. He had taken it to several local places - some thought the shop had put in the wrong bore MC (see my previous threads on this...). But, now I'm thinking they just did it the way Ron described - didn't take the time to do it properly - and everyone since (myself included) has just figured they were adjusted properly...

Try my suggestion and see what you learn. Hopefully the answer has always been that simple......tighten up those rear shoes, over and over (and over) again with the rear axle raised, trans in neutral, and the tires kept on for good turning leverage.

[PUCampin]

My first car was a 75VW with 4 wheel manually adjusted drums. When I was learning to work on that car, an old mechanic taught me how to adjust drums much the way Ron described. In my case I would adjust until it started to scrape. Then hit brakes hard a couple times. Spin and adjust some more. Hit brakes hard. Then adjust until it locked the wheel up tight, then back off until it just scraped a little. Hit brakes hard and check. Adjust again if required. I have had success with this method on multiple drum vehicles and my trailer which will lock all 4 if I slam the manual activation lever. Drums are a lot more work than disks, and adjusting them properly is becoming a lost art. I feel many of the complaints regarding drums is them being adjusted. Notice what most all big rigs have on the drives and trailers?