E30 Heavy duty rear backing plate or engineered removal

[noid]

One thing that frustrates me with the E30 is the OEM backing/dust plates:

1. You cant remove them without removing the hub (and thus the bearing)
2. They bend extremely easily when you have strut/trailing arms out for work
3. E-brake is dependant on the weak rear backing plates staying straight
4. Because of rust or fatigue, E-brake work leads to locking pins/ebrake cable being ripped out.

I have eliminated the front dust plates (good riddance). Does anyone know of any heavy duty backing plates on the market for the rear that can support the E-brake setup, or an engineered solution to remove the backing plates yet install something to retain the E-brake setup?

[roguetoaster]

I concur, the design is faulty. However, they are cheap enough to replace with new ~$30 per side, which should solve all of the issues you are experiencing with fatigue & etc.

Perhaps if/when you replace them you could weld in a washer or similar to reinforce the slots for the spring ends?

[agent]

I have eliminated the front dust plates (good riddance).

Did you put anything there or just leave it open?

[TimKninja]

There is a way to use a larger washer /different parking brake hardware on the stock backing plates so you don't have to replace them . I fixed one car awhile back by fabricating a larger washer for the Ebrake hold down pin to lock on to .

On a few E36s I cut a chunk of unneeded material out of the backing plate and then slid over the backing plate and bolted it on. Worked mint .

I didn't attempt ethier repair on my car , I just used rust free trailing arms during my 5 lug swap

[noid]

I concur, the design is faulty. However, they are cheap enough to replace with new ~$30 per side, which should solve all of the issues you are experiencing with fatigue & etc.

Perhaps if/when you replace them you could weld in a washer or similar to reinforce the slots for the spring ends?

~$30 per side, until you take into account the cost of new bearings (if already new).

Did you put anything there or just leave it open?

Completely removed, nothing in place of. They really aren't needed.

[roguetoaster]

~$30 per side, until you take into account the cost of new bearings (if already new).


Completely removed, nothing in place of. They really aren't needed.

You could always do this without removing the backing plate if yours isn't totally rotten.

Isn't the backing plate supposed to be there to keep water off of the rotor?

[noid]

You could always do this without removing the backing plate if yours isn't totally rotten.

Isn't the backing plate supposed to be there to keep water off of the rotor?

In the front, its more for dust than anything. The whole keeping water off the rotor is something I have also read, but doesn't make much sense considering 1 side of your rotor is exposed, and having the water pool at the bottom of the dust shield lip adds more moisture then takes it away (allowing the rotational force to shed the water).

The other thing you get people saying is that it is designed to shield the brake disk assembly from rocks getting in there, but again, if anything, the dust shield traps rocks in the space between the shield and the rotor.

The third thing you hear is that it is a shield to prevent sticks or other debris from jamming into your rotor. However, anything strong enough to lock your assembly up would also very easily bend the dust shield right into your rotor, so that point in moot.

The added benefit to removing the shields is more air flow and more even cooling.

Now if only someone made heavy duty bend resistant rear backing plates.

[mr2peak]

Dust shields are there to stop brake pad dust from ruining the finish on your wheels. It's very corrosive and hard to clean up. If you don't absolutely have to remove them, leave them in place.

[agent]

The added benefit to removing the shields is more air flow and more even cooling.

Something tells me that if this were the case, BMW would have just left them off the car. I'd be curious to see some empirical evidence of the air flow around and past the brake rotor and wheel assembly with and without the shields in place.

Dust shields are there to stop brake pad dust from ruining the finish on your wheels. It's very corrosive and hard to clean up. If you don't absolutely have to remove them, leave them in place.

That would make a lot more sense if they were between the rotor and the wheel. That said, their shape (in conjunction with the air ducts in the front valence) isn't arbitrary. They appear to channel the air so that dust gets blown past the wheel assembly as well as through the holes in the wheel itself.

[agent]

Forgot to add that I also think the design of the dust shields helps keep the ABS sensors clean(er).

[noid]

Something tells me that if this were the case, BMW would have just left them off the car. I'd be curious to see some empirical evidence of the air flow around and past the brake rotor and wheel assembly with and without the shields in place.

That would make a lot more sense if they were between the rotor and the wheel. That said, their shape (in conjunction with the air ducts in the front valence) isn't arbitrary. They appear to channel the air so that dust gets blown past the wheel assembly as well as through the holes in the wheel itself.

There is always a trade off, I highly doubt the marginal increase in cooling was a concern for a car sold as a street car.

Its not just air flow, its also radiant heat, you get heat retention from the dust shield that you do not get on the other side of the rotor.

If you look at race car brake assemblies, they either a. run no dust plates or b. run plates that funnel air from ducts.

https://www.google.ca/search?q=race+car+brakes&source=lnms&tbm=isch&sa=X&ved=0ahUKEwi6td6Swd_JAhWyo4MKHYG3APwQ_AUIBygB&biw=1920&bih=955

Probably because the brakes they run are unique enough to not have a matching dust plate available, but that also means that they are not important enough to manufacture.

For all we know they are on there because it prevents mechanics from burning themselves while working suspension components near the rotor, or maybe its something "that has always been that way", maybe its cosmetic, maybe its something else.

What I know for sure is that; since I have had them removed I have had no ill affect, and anyone else I know that has removed them has had no ill affect. Sometimes logic and empirical evidence makes more sense than trying fit a reason to an existing component.

[agent]

Do you track the car you took them off?

[roguetoaster]

I wonder if they might also be in place to keep oil and debris of that nature off of the rotor in a purely CYA manner by the manufacturer. But it seems equally likely that they are a carryover from drum brake design.

[Kershaw]

Its not just air flow, its also radiant heat, you get heat retention from the dust shield that you do not get on the other side of the rotor.

Radiant heat is an interesting point to bring up. On IXs, especially ones that are lowered, the passenger front pops quite often. The exhaust stresses the cv boot near it so much it will pop before all the others. Race cars wouldn't care, I bet they get new axles every other race. But longevity on a street car is definitely a consideration. I rarely hear of rear cv boots popping. Maybe the shield does something in that regard, the cv joint is directly behind the brakes. Although, you'd really have to be on the brakes a lot to put out anywhere near the kind of heat the exhaust puts out. Maybe they considered Schumacher getting groceries on a daily basis.

[nando]

I partially melted the outter CV boots on my ix from hot brakes. it actually isn't that hard to heat up the brakes hotter than the exhaust - the highest temp I recorded was over 900 degrees IIRC. I don't think the shield helps though because it can just transfer through the hub into the CV shaft, and not having a shield would have probably resulted in cooler brake temps to begin with.