Booster change to run Volvo 240 (four-pot) calipers?

[Alfetta77]

Hi everyone, would the standard brake booster fitted to and Alfetta GTV be ok to run Volvo 240 calipers, or is a different / upgraded unit required? Thanks in advance for any advice.

[LukeC]

It's not the brake booster that is the issue.

By the letter of the law, a brake upgrade such as this requires and engineering certificate. If the volume of displacement of fluid in the replacement callipers (simple schoolboy maths i.e. area of two pistons versus area of single piston) is significantly greater than the original calliper, then a proportional increase is generally in area is required in the master cylinder. This is to ensure there will not too much brake travel and pedal effort will remain similar. This is stipulated in VSB 14 (National code of practice for modified vehicles).

I converted my front brakes to GTA 305 mm discs and 4 pot Brembos when I did my 3.2 conversion. I changed the master cylinder from a 22 mm to a 24 mm. Sailed though the brake test.

But I can still get them to fade on a hard run... 

[Alfetta77]

Cheers Luke, that makes sense.

[SimonR]

I changed my 1984 2.0 GTV to Volvo 240 calipers along with larger 184mm Alfa164 vented discs and did not change anything else and it is all working fine,  we did discuss the possibility of adding a proportional valve inside the cabin however it does not appear necessary at this stage. Brakes are now significantly better than the prior Brembo Alfa 75 upgrade that was done years earlier.

[Anth73]

My GTV has run the Volvo dual pot brakes with the standard master cylinder without problems. The brakes are powerful despite some initial softness in the pedal.

I'm upgrading to GTA 305mm ftont brakes just like LukeC. Current thinking is to try the standard master cylinder.

Luke - which car did your 24mm master cylinder come from?

[Alfetta77]

Thanks Simon and Anth, sounds like it will be straightforward.

[LukeC]

which car did your 24mm master cylinder come from?

Hmmm: Some type of Mercedes Benz. I think a W116 series V8. The ports are on the other side so there is some line work to be done.

[GTVeloce]

Isn't the 164 MC 24mm? Or maybe 23mm? I recall it is bigger anyway!

[Duk]

My 75 had a good pedal with a standard MC and the Volvo 4 piston calipers.

[rowan_bris]

I used a 25 mm cylinder with Giulietta QV calipers on a GTV6.  It is an ATE cylinder which comes on a BMW 750

[Anth73]

I used a 25 mm cylinder with Giulietta QV calipers on a GTV6.  It is an ATE cylinder which comes on a BMW 750

Was that a drop-in replacement? If so I'd like to know the specific model of master cylinder for my own Brembo 305mm upgrade. 

[rowan_bris]

There was a bit of work on the pipes but nothing too hard.  I don't have the number handy but will have a look

[rowan_bris]

It was for an E32 BMW - Ate 010210

[Alfetta77]

Hi Rowan, were you able to use the Alfetta reservoir, or did you have to use the BMW one? Have tried to look up dimensions / technical drawing of the Ate 010210 but haven't had any luck.

[rowan_bris]

I used a BMW one