Pete

[205nut 0]

Hi, I've not posted on here for a while and I'm not sure whether I've posted in the right area. Apologies if not. Thing is I've bought a new brake master cylinder for my 1.6 gti and the car is in the garage being worked on. I've now realised that the 1.6 and 1.9 gti may have different master cylinder bore sizes, 19mm and 20.6mm although a compatibility chart I saw on one website seems to suggest that both versions may have had 20.6mm version until 1988 after which it may have only been spec for the 1.9gti (see below for the chart). The question is whether members have any experience with different the two different bore size cylinders and whether I'm doing right fitting a 20.6mms bore unit to my 1.6gti? My intention was to stay original and I'm guessing I may experience a shorter brake pedal travel with the cylinder I've bought? And a firmer push on the pedal required for the same level of braking? Thanks in advance for any help, Pete

[welshpug 1,650]

either will work just fine, the larger should give a shorter pedal indeed, though I doubt you will notice the difference unless you compare brand new vs brand new, I can't find any specific listing denoting any application variances.

 

the main difference between 1.6 and 1.9 is the 3 line vs 4 line plumbing, 1.6 uses a single line for the rear brakes with an inline pressure reducing valve mounted on the chassis leg in the engine bay,   a 1.9 will have a diagonally split 4 line system with an inline pressure limiter for each side mounted just ahead of the fuel tank.

 

replacement master cylinders for this application should have a blanking bung included so make sure that's in the box, oem cylinders were listed as 3 and 4 port in both sizes.

 

 

I wouldnt trust the ebay listings  

Edited October 5 by welshpug

[pug_ham 244 3 Cars]

If your car still has the original master cylinder fitted then there should be the size marked on the casting, which imo should be marked 20 for a GTI, either 1.6 or 1.9.

 

What size did you buy?

 

g