Master cylinder upgrade

[Jamese30]

Hi All
I am thinking of doing a brake upgrade on my 327, which has drums on the rear still. Wanted to upgrade the original 320i master cylinder.

Is the best like for like change still the one from the e32 750? I read something about some people using Clio master cylinders somewhere?


Any tips would be great.


Thanks

[daimlerman]

Plastic wing Clio's donate their brake servo when one installs an M50 type engine..they are made by Boch so are quite suitable for proper cars!

You will gain a little by fitting disc rear brakes,but unless you drive everywhere at max speed there is little gain apart from slightly easier servicing.

Fitting stainless steel braided flexi's and fresh fluid will sharpen up the standard offering,as will using a decent quality pad.

[maggspower]

You will only need a bigger M/C if you have upgraded the calipers to large single pot sliding calipers e.g e32 750i ones, or somthing like 4 pot calipers. If you go for the rear disc setup then the standard 23mm M/C will be suited.

You only need a bigger M/C if you need to shift more fluid at the caliper end, i.e you have a long brake pedal travel before hitting the brakes.

The clio servo is to give added clearance for engine swaps.

If you want to stop quicker, just give your brakes an overhaul and fit some decent pads.

[Jamese30]

I've got flexi braided hoses fitted and want to stay with drums, just wondered what was the best master cylinder upgrade. Does a Clio one have a larger piston then?

[maggspower]

I've got flexi braided hoses fitted and want to stay with drums, just wondered what was the best master cylinder upgrade. Does a Clio one have a larger piston then?

You cant up grade the master cylinder as such, you just need one that matches the brakes you have. BMW got it right so there is no need to change it unless you are up grading the calipers. You are not, so leave it alone.

The part from a clio that is used is the servo, this is not an upgrade either, it just gives more room to fit different engines.

If you want to stop quicker, just give your brakes an overhaul and fit some decent pads.

[Jamese30]

I've got good pads all round (mintex) and new fluid but too much travel. The only reason I asked was I know people change master cylinders on the m3 to the 750 unit just increas braking pressure and pedal feel - larger piston area equals less travel to apply same force...

[scjimbo]

I've got good pads all round (mintex) and new fluid but too much travel. The only reason I asked was I know people change master cylinders on the m3 to the 750 unit just increas braking pressure and pedal feel - larger piston area equals less travel to apply same force...

Surely this will cause issues further down the line with drums. In normal driving it would be fine. However if you get the brake fluid hot, bringing down the viscosity, then jump on the brakes, wouldn't it force the fluid past the slave cylinder seals?

[reggid]

how does the clio servo compare to the 325i servo? in terms of diameter and depth ?

does it reduce the assist, increase it or is it the same?

[daimlerman]

how does the clio servo compare to the 325i servo? in terms of diameter and depth ?

does it reduce the assist, increase it or is it the same?

Stock E30 item is large in diameter and thin in depth.
Clio item is smaller diameter but thicker,so you need a spacer rod to enable the pedal linkage to pass through the servo to the m/c.So,in other words,you can adjust the pedal free play by swapping spacers.I made several before finding one that 'felt' right and did not allow the brakes to bind once warm.

Assistance is broadly the same,I have one E30 with an M20 and one with an M50,and the 'feel' of the brakes/pedal is pretty much the same between the cars.

[reggid]

how does the clio servo compare to the 325i servo? in terms of diameter and depth ?

does it reduce the assist, increase it or is it the same?

Stock E30 item is large in diameter and thin in depth.
Clio item is smaller diameter but thicker,so you need a spacer rod to enable the pedal linkage to pass through the servo to the m/c.So,in other words,you can adjust the pedal free play by swapping spacers.I made several before finding one that 'felt' right and did not allow the brakes to bind once warm.

Assistance is broadly the same,I have one E30 with an M20 and one with an M50,and the 'feel' of the brakes/pedal is pretty much the same between the cars.

do you know the difference in diameter and thickness?

[daimlerman]

do you know the difference in diameter and thickness?

Just been in the garage with a tape measure for you!

Stock is about 9''x3''
Clio is about 7''x4''....this leaves about a finger width clearance to the M50 inlet.Stock m/c bolts up,pipes needed a little bend,and a suitable spacer to extend the pushrod is required.

[Jamese30]

Thanks willnz
Appreciate the advice. I might adjust the pedal first then.....


Thanks guys... Great help as usual, I appreciate it.