21 replies to this topic

[booton]

i was wondering if any one has rear drums that have been drilled to improve the rear braking.

and they opinions on them.

i've been told its a good option as it increase the surface area of the drum and reduces the heat and weight thus creating better braking. ( but you would wear out shoes quicker)

your thoughts

[MRA]

That all depends on where you drill the holes

[Burnard]

Looks like someones keeping it a well guarded secret ...

[booton]

would be drilling the hole in a stagged three pattern around the out side of the drum where the shoes touches the drum if tha makes sense

[mike.]

Wouldn't that reduce the braking area? Since you'll be removing aload of it...

[booton]

it work the same way as drilled brake disks.

the holes would be more abrasive on the pads.

[AndrewJ530]

But wouldn't that increase the heat produce by the friction between the pad and drum therefore causing the drum to expand faster, which in turn, would make the brakes fade quicker? Just a thought.

[booton]

i agree with the fact that it would wear out the shoes but they only cheap and worth it for a little bit of breaking

as to the heat i think the holes would allow air to flow though the drum cooling it which would greatly reduce the heat build up.

as the whell rotates when driving more and more cool air would cool the drum inside and out.

[MRA]

Drilling the friction surface would reduce the contact area, but as above would reduce brake fade as the gases can escape easier, however makesure that there are no sharp edges, which really means don't use a drill to finish the hole, use a reamer or similar and countersink both faces, then add a radius to ALL of the new edges

But don't tell anyone else....... as it is a closely guarded secret

[MRA]

also unless you have some pretty severe front brakes then it is doubtfull that you will need to improve the rears to this extent

[booton]

this something i going to as i have a spare set of cooper drums.

just going to take a while on the old pillar drill lol.

was thinking 5mm hole three accross stagged e.g -

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Edited by booton, 16 June 2010 - 11:05 PM.

[Stevee]

why would you need to improve the rear brakes

just get wider shoe's and some Mini Fin's

your rear braking is only 25% Ish of all your braking the rest is done on the front where all the wight is going towards!

i could see if you did it on your front's

but then id personal get rid of the drums on front and stick some 4pot 7.5 calipers on they'll stop you (y)

[booton]

i have 8.4 disks on the front they do a pretty good job.

but my back brakes are not the best they are fitted correclty and adjusted right, passed the mot etc but they just not good enough.


u said u can get wider shoes didn't know that.
and mini fins are expensive where as i could spend an hour to in the workshop drilling these.

[lrostoke]

Sounds more like you still have a problem with the rear brakes, from previous posts you've got a 998 upgraded a tad but not to extreme.
Your setup should work no problems.

I'm on drums all round and they were strong enough to stop mine even pulling a trailer.

Like mentioned brakes are biased to the front, you upgrade the rears to much you'll just end up locking up the rear.

[Stevee]

yeah mini's after 1984 had wider drums and shoes on the rear

and i think auto's did aswell

i run drum brakes all round but i hate drums

i don't trust them!! at least with discs if they brake you still have a bit of braking