hi folks, i thought i'd just share a little nugget of info i worked out today when i was up the breakers yard getting some bits.

the 25mm brake master cylinder from an 89 audi 100 quattro is a direct swap for the standard 22.2mm felicia one, it just bolts straight in and all the hoses line up perfect... dont know about the abs model as it was a non-abs one i was fiddling with

could be useful for anybody beefing up the brakes a bit

oh yeah and one more thing before i forget, the 5 stud centre wheel hubs from a mk3 golf vr6/gti fit in the felicia wheel bearings too. the plan i've quickly formulated whilst i had having a pint of carlsberg is to attempt to fit 312mm 5 stud brakes to my pickup, and fit mk4 golf 5 stud rear discs too... ayway... word out... more on this later

I know Audis even less than Skodas, but I think there is also FWD Audi 100 produced in years mentioned and it is at least here in Finland it could be even more common than Quattro. The question: is there diffrence in that cylinder between FWD and 4WD Audi, can you confirm, Tom?

Thanks anyway for the tip, maybe not buying pedal box yet...

the fwd ones have a 22mm cylinder i believe...

ebay linky

@felrace: is yours left hand drive?? i'm assuming so right? you would have to check it will fit a left hooker tbh, the brake servo may not be the same as a rhd model

Why would you want a larger M/cyl?

so i can use gert big calipers like the ones off a octavia vrs instead of the wincy ickle ones on a felicia

edit: i think only the 2.3 quattro has the 25mm one, the rest have a 22

Why would you want a larger M/cyl?

Yep I think it's something to do with "fluid dynamics" if that's the correct technical term. Bigger bore = more fluid pushed through = more force at brakes especially if the piston thingy is bigger. Or something like that anyway.

that's exactly the point thought, the standard felicia master cylinder is bordering on being too big as it is for the standard calipers, hence the hard pedal feel in a felicia...

but i was thinking something a bit beefier, tbh the brakes in my pickup i find so bad they are scary

Yep I think it's something to do with "fluid dynamics" if that's the correct technical term. Bigger bore = more fluid pushed through = more force at brakes especially if the piston thingy is bigger. Or something like that anyway.

Well, that was kind of my point - that's exactly the opposite to how it works; unless you're changing cylinders and calipers to suit, a larger master cylinder will lead to lower brake pressure. Counter-intuitive, but that's how it works; it's about the amount of pressure that's generated in the system once the pistons have all stopped moving. It is, of course, a compromise because you need fluid volume movement to get them there in the first place, but it's not as simple as "bigger master cylinder = better brakes".

Well, that was kind of my point - that's exactly the opposite to how it works; unless you're changing cylinders and calipers to suit, a larger master cylinder will lead to lower brake pressure. Counter-intuitive, but that's how it works; it's about the amount of pressure that's generated in the system once the pistons have all stopped moving. It is, of course, a compromise because you need fluid volume movement to get them there in the first place, but it's not as simple as "bigger master cylinder = better brakes".

Yep, and fitting bigger master cylinder is really not same as using pedal box, that my previous phrase would have been worth of smiley .

BUT, if using pedal box and original wheel calibers, how big should bore of m.cylinders be? In grA. homologation there are 15,9, 17,8, 19,1, 20,6 and 22,2 mm cylinders listed for PB. When original front calibers are with 54 mm pistons and rear ones 19 mm, how should bore of m-cylinders be counted? Is it only question about adjusting the stroke with PB system or should the bore for front and rear be different?

A bigger-bore master cylinder will give you a harder pedal feel because the leverage will effectively go down. However, if you're fitting bigger calipers you'll need a bigger master cylinder because the small one won't have (well.... might not have) enough pumping action to push the bigger pistons out far enough. Bigger m/cyl plus bigger calipers should give similar pedal feel, all else being equal (er, which it won't be, but never mind!).

oh yeah and one more thing before i forget, the 5 stud centre wheel hubs from a mk3 golf vr6/gti fit in the felicia wheel bearings too. the plan i've quickly formulated whilst i had having a pint of carlsberg is to attempt to fit 312mm 5 stud brakes to my pickup, and fit mk4 golf 5 stud rear discs too... ayway... word out... more on this later

orite mate do you know if the gti carriers and calipers will fit to the felicia hubs, as i pulled a set of at a breakers yard a while ago,thinking they may fit.

cheers

mortonvw

hello morton vw. no none of the vw carriers will fit on the skoda hubs, the caliper/disc offset is totally different for a start, and the holes are tapped on the vw hubs and plain on the skoda ones. the hole spacing is 90mm centres on the skoda ones and from memory i think the vw gti ones are 76mm but i would have to check... next thing, the hole in the centre of the brake disc is 60mm on the skoda disc and 62mm on ALL vw discs so yo need to make a spacer ring.

all this said, it's still not impossible and it would be a simple case of manufacturing a few brackets to fit which i will be doing sometime in the near future so if you want a set drop me a line and i may be pursuaded to make a couple of extra ones for beer tokens. then you could change the centre hubs for the early mk3 golf 1.4/1.6 one which will have the right size spigot for the brake disc and has 4 studs etc or i can make a few spacers to fit the felicia ones

tom you say that the vw disks will need spacers but if the inner hub off the gtis will fit then the vw disks shud fit straight on. if you were to be making some adaptors i would be very interested in a set or a couple of sets at the right price.

mortonvw

yes the vw hubs do fit but i was thinking more if you cant be bothered to press out the hub and risking breaking a decent wheel bearing and having to take it all apart.

here's what i did when i did a 4 pot conversion

made an aluminium 'ring' on my lathe to go over the 60mm brake disc spigot to make it upto 62mm

hub re-assembled with golf g60 280mm front brake disc

here you can see the vast difference in size, vw g60 disc vs standard felicia disc

So do the g 60 brake carriers bolt to the felicia hubs or do you still need to make some adaptors.

no, the g60 carrier wont nor will ANY vw carrier, essentially the g60 carrier is the same as a gti ones but they are 12mm taller

So wots the solution to running bigger brakes. Do any of the carriers of newer skodas fit or are they just same as vw now,is it a case of manufacturing some mounts.

no, the g60 carrier wont nor will ANY vw carrier,

third time lucky:rotz:

you would need to make an adaptor bracket to go between the vw carrier and skoda hub