drum to disc conversion

[nzer]

Well i'm here taking it all apart - yet i'm still not sure if I need to change the master cylinder. My master cylinder looks exactly the same as the one I got- same brake lines and everything.

Any thoughts?

The car i'm working on is a 84 320i - donor car was 88+ 316

316 master cylinder + booster :

[/list]

[trent]

Re: drum to disc conversion

Well i'm here taking it all apart - yet i'm still not sure if I need to change the master cylinder. My master cylinder looks exactly the same as the one I got- same brake lines and everything.

Any thoughts?

The car i'm working on is a 84 320i - donor car was 88+ 316

316 master cylinder + booster :

[/list]

Yes, you do need to change. Just because the MC's look the same, does not mean the inner bore size of the pistons is the same. Drum brakes need a LOT more pressure than disk brakes. You should switch to a MC ment for 4 wheel disks.

[mcgrath]

I have converted my 85 318 to disc brakes. front and rear are from an 87 325i. I still use the MC from my 318 and all four wheel lock at the same time.

[nzer]

I have converted my 85 318 to disc brakes. front and rear are from an 87 325i. I still use the MC from my 318 and all four wheel lock at the same time.

I haven't changed the front brakes - Just replaced the both trailing arms from drum to disc.

Trent: If the diameter printed on the MC is the same - are they then interchangeable? I was orginally thinking there may be some difference in brake bias?

[e30evolution]

Re: drum to disc conversion

Well i'm here taking it all apart - yet i'm still not sure if I need to change the master cylinder. My master cylinder looks exactly the same as the one I got- same brake lines and everything.

Any thoughts?

The car i'm working on is a 84 320i - donor car was 88+ 316

316 master cylinder + booster :

[/list]

Yes, you do need to change. Just because the MC's look the same, does not mean the inner bore size of the pistons is the same. Drum brakes need a LOT more pressure than disk brakes. You should switch to a MC ment for 4 wheel disks.

drum brakes need less pressure... they are servo activated

it should have the bore diameter stamped on the mc somewhere.... could be a 17

[nzer]

Re: drum to disc conversion

Well i'm here taking it all apart - yet i'm still not sure if I need to change the master cylinder. My master cylinder looks exactly the same as the one I got- same brake lines and everything.

Any thoughts?

The car i'm working on is a 84 320i - donor car was 88+ 316

316 master cylinder + booster :
]

Yes, you do need to change. Just because the MC's look the same, does not mean the inner bore size of the pistons is the same. Drum brakes need a LOT more pressure than disk brakes. You should switch to a MC ment for 4 wheel disks.

drum brakes need less pressure... they are servo activated

it should have the bore diameter stamped on the mc somewhere.... could be a 17

The new MC (from the all disc car) has 22 stamped on it - so I'm assuming my drum one WILL be diff then. Oh well - its just a bitch to get to it with the stupid 6 cylinder L-Jettronic cars.. no space in the engine bay cause of all the vacuum hoses.

[e30evolution]

look for another stamping on it.... because 22 is pretty big..... non m e30s have 17mm and m3's have 19mm ..... i got mine for a 750il so it is 25mm

[Rob]

how much of a difference in braking does the rear disc conversion make? i'm curious

[boom-monkey]

Not much, but it sure is a hell of a lot easier to change pads then shoes. Plus for more spirited driving the discs will cool down a lot faster than drums. Plus there are more performance pad choices out there as opposed to 2 maybe 3 shoe choices.

[nzer]

look for another stamping on it.... because 22 is pretty big..... non m e30s have 17mm and m3's have 19mm ..... i got mine for a 750il so it is 25mm

Interesting - it has 22 and 17 stamped on it in difference sections?

This is a pic from the disc brake master cylinder.

[nzer]

how much of a difference in braking does the rear disc conversion make? i'm curious

At this stage and on this car (my mums) its easier to replace with discs than do drums.. I got everything i need for the swap , MC, brake lines, 2 trailing arms with disc + caliper for 150 kiwi dollars.. like 75 US.

I did a track day in that 320 when it was drums and it was fine.