Rear disc conversion ?

[Wal33]

Could I have your advice on this one please, is it worth coverting my rear drum brakes to discs, I've sourced the parts, and read the guides I can find and mechanically it's an easy fit, but do I need to worry about the braking setup/ brake bias and so on? Electronics are not my strong point !

Edited May 23, 2019 by Wal33

[isetta]

I don't know anything about the brake bias. But are going to notice any difference to the car doing this. Unless you drive like a madman I can't believe there will be any advantage to you

[Wal33]

This is the first car I've had in 15 plus years with drums on, and my commute through Wales is all A road, so the brakes heat up fast, if it was motorway miles I'd agree with you, but I wouldn't want a tractor pulling out on me (happens a lot round here) and needing to stop with red hot drums on the back, plus there's the aesthetics of them with nice wheels.

[Luke4efc]

The rear brakes do something like 15% of the overall braking force. Even if you are using them all the time and heating them, you wont gain much.

That being said, it does look a lot better than drums, especially once you paint them red to get an extra 5hp each side.

[mastachaz]

7 minutes ago, Luke4efc said:

The rear brakes do something like 15% of the overall braking force. Even if you are using them all the time and heating them, you wont gain much.

That being said, it does look a lot better than drums, especially once you paint them red to get an extra 5hp each side.

red calipers are more like 10hp 🙂

[zain611]

On my fiesta I upgraded both sides to the ST brakes. The front brakes are more noticeable in stopping power. When I did the rear discs conversion I did still feel a difference in braking. The thing with drums are if the auto adjustments goes you'll need to adjust it manually and the drums don't engage properly until you press the pedal further in in which the front brakes would be doing a lot more braking. When I did the conversion of the rear brakes I noticed just by pressing the pedal normally now it feels like all brakes engage front and rear and I'm sure braking power was better. 

[bashbarnard]

Drums actually create far more braking force than discs if adjusted correctly. Because they have a far greater surface area contact and also have a self servo effect. That being said they do not dissapate heat as fast. The last 306 I built I actually kept the drums and fitted a GTi axle. Reason being is they're better for road use imo. Even on track days I've done and I've done a fair amount. They never once overheated. It's always the fronts to go.

[Eric Bloodaxe]

Certainly I never noticed a deficiency in braking on cars with rear drums - at least on the road with sensible driving. Different story for track work I guess. Weight transfer does mean the fronts end up doing most of the work, particularly noticeable on a bike where you get 2 enormous front discs and something the size of a small saucer on the back.

One drawback I used to find with drums, which is eliminated by discs, is problems with adjustment - both manual and auto adjusters are prone to seizing, so you need to keep them well maintained. The drawback with discs is the handbrake is often not as good. With a drum, as it cools it contracts towards the brake shoes, with a disc, it contracts away from the pads. As ever, leave it in gear when parking!

 

[gillyallan]

I just couldn't take another 2 wheels I'd have to heavily clean. Can I convert the front to drums too lol

[JW1982]

I will never ever buy a car with rear drum brakes. My previous Focus MK2 did have rear drum brakes. Despite being in perfect (like new) condition the brake performance of the drum brakes was pretty poor and the handbrake was rubbish. After I converted the car to rear disc brakes the brake performance improved significantly. Especially when braking at high speeds (German motorway) the car remained much more stable. The handbrake also improved significantly. 

My current Focus MK3  1.0 ECOboost did have rear disc brakes as standard (most European countries did have rear disc brakes as standard on all versions of the Focus MK3/MK3.5). The Original brake pads of the Focus MK3/MK3.5 disc brakes perform fine but produce a sh*tload of brake dust. I solved this permanently by replacing all brake pads. I installed ceramic brake pads at both the front and the rear of the car which improved brake performance and reduced the amount of brake dust by about 95 %. I have not cleaned my wheels in 2 Months and apart from some road dirt they are still perfectly clean. 

[Wal33]

Thanks for the replies,  from what I've read it's an easy upgrade to do in the garage and relatively cheap as well so why not start with the discs. I don't even know if it's just MY drums not being adjusted properly as I've not taken them apart but the whole set up feels wrong if braking at high(ish) speed.