GTI 16V cutting out when braking, help appreciated !

[Mark G]

I have a 1990 (H) MkII GTI 16V  and its just had a new cambelt/timing belt, fan belt and a full service. On this occasion the work was carried out by a recommended garage that I had not used before (ex police apparently), reason being was that their quote was very reasonable and my funds are extremely low.
The first couple of days since getting the car back its been fine, but on the third day its started to cut out when braking which I have found fairly dangerous when braking to turn a corner as the power steering goes as well. Last night I spoke to a friend of mine who believes it could be the timing belt not fitted properly or the idle pump. This morning the garage in question have said that the timing belt is fine but they suggest the pump be removed, cleaned and replaced, this should solve the problem.
As you can tell I am not a mechcanically minded GTI owner and any help would be much appreciated.
Many Thanks
Mark.

[Gambit]

the car just needs setup correctly, which obviously the ones who fitted the timing belt didnt bother to do

http://www.btinternet.com/~gvk_motorsport/16valvestall.html

[Mark G]

Thanks for that information Gambit, I appreciate that. I will print off the link you provided and return the car to the garage.
The only other issues I have with mine is that the heater does not work (the matrix re-call was performed apparently) it only blows cold air, the bulb has gone for the speedometer (which is discussed on this page) and I need new exterior trim for the rear window screen.
I am based in North London and if anyone knows any good mechanics for these MKII's that are helpful and won't hurt my wallet, I would really appreciate the advice. My car is all original 3 door in oak green and I'd really like to get her back into A1 condition.
Many Thanks.
Mark 

[Gambit]

your heater its possibly airlocked.
to bleed the system
1. take the top of the expansion bottle
2. set the heaters to max heat
3. start the engine and let it idle till the water in the expansion bottle boils (or fan quicks in). also squeeze the water pipes coming and going from the radiator
4. stop engine, top up expansion bottle and put top back on tight!!

if that doesnt cure it then the bypass valves maybe faulty but that can be explained at a later date!!

as for the rear window trim i assume you mean the black sticker round the window? http://www.gpcvwaudi.com stock them

[Mark G]

I really appreciate the advice Gambit, I realy don't feel too confident on doing these jobs but I'm up for the challenge.
All the very best.

[Gambit]

ah you'll be fine!!