nobody has mentioned that without the ABS, these cars do like to lock up..so just be aware with 280 if you hit the pedal too hard you will just be making smoke anyway
Yeah if you have a 700 hp 3.2 with 256 brakes and small MC you'll lock up easily if you stamp on it (Unless you have wide and very very sticky tires) you just get fade overtime which can improved a lot with better pads as Toyo says. MC vs calliper size is arguable more important, when you put a huge MC on you get "better" pedal feel but also end up having to have Schwarzenegger to stop. If you can't lock the wheels with 280 mm discs, try putting a 22 mm MC back in and you'll probably find you brakes now feel as "sharp" as the other MK2
My experience with 280mm brakes/25mm master cyl and toyo proxes r888r…i get increased pedal presing effort but I cannot lock the brakes ! I have it pd150 converted running over 350 Bhp… On my other mk2 golf with 1.9 AFN engine I have 256mm front brakes, they are a lot sharper than the other mk2 !
If you have 54mm pistons on those 280 brakes a 25mm M/C pushes more fluid volume than the pistons can accommodate weakening the caliper clamp force. It also reduces the line pressure.
I have to change discs and pads soon, bought textar discs and pads nearly a year ago…will measure the piston sizes when I get to it ! I have mk3 vr6 running gear if it makes any difference…wide front axle, rear disc brake conversion and 5 stud wheel hubs…
I think they're also 54. It's marked into the front of the caliper casting on the girlings. Ideally you need to go back to 22.2mm for non abs cars. This will increase the line pressure and clamping force.
To be honest when I bought the car it had a cast iron brake master cylinder and it was faulty, I had to try a few till I found the t4 2.5 tdi fits ! I will live with it for the time being, I will upgrade brakes soon as at the power levels of the car o feel 280mm are not enough ! I have a 312mm brake setup but I have to switch to 16” wheels which will be a trade off in comfort + I just bought another set of toyo slicks so I have to wait till these wear out as well ! Thanks for your replies gents !
Interesting. Sorry to hi-jack the thread slightly but I've never been that impressed with the brake pedal feel on my Mk2 with G60 280 brakes (long travel)...and it's just dawned on me the master cylinder in it is a 23mm Seat one from an originally ABS'd car. So potentially a smaller stock 22mm could sharpen things up?
Potentially, but at the expense of a longer pedal. Personally, I'd be trying a better type of brake pad. A fluid flush, as it's SO easy have air trapped in the rears. Also properly setting up the rear calipers can help make the brakes respond much better
It's actually worse than 23mm. I think it was 23.8mm (107.2%>) when I looked at it and the 25mm is 25.4mm (114.4%>), but it's the translation into line pressure and subsequent effect on clamping force that really matters. I agree it is absolutely essential to set up the rears correctly to eliminate pedal travel. Firstly having them wound out right mechanically for the handbrake and also fully bled. The former can be quite dramatic in a Mk2 with 38mm stock rears. I think maybe the oversize gives you that good initial feel as it quickly closes that initial gap on the rear, but once the rear starts to come up and you're entirely on the front that glass/wooden feel comes on. The rears have to be spot on first, but on a 22.2 you will gain line pressure, clamping force and better modulation. Imo the rears should go back to the original 36mm spec too.
Each to their own but I have never understood (unless you're tracking it) the necessity or call for beefier brakes on the 16V (256mm) with the 22mm M/C I drove the beejesus out of my '91 16V and the brakes never faded or failed but with a couple of caveats: As others have said - top quality pads - waste of time without them Ensure that the brake fluid is in top notch order - I always used ATE and it's been great Confirm that all calipers are in good working order - not binding, seals/pistons OK I did have grooved front discs - I think they were Brembo The thing stopped on a tuppence but if you're set on 280mm away you go but I'd spend the cash on something else.
This emphasis on setting up the rears is really interesting. I feel my rears aren’t really contributing properly cos when I brake hard I get a fair bit of nose dive and the overall impression that my brakes aren’t as sharp as they should be. It’s hard to judge cos I’m going between driving my 16v Mk2 with the 256mm and 38mm setup which is sharp, and my early 8v (1984) which has 239mm and 36mm which may have a problem. I’ve adjusted the rears properly so that the handbrake works well, but I think my rear bias valve isn’t adjusted properly after a strip down of the rear beam to do the dreaded bushes. How do you guys correctly adjust the position of the spring on the rear bias compensator baring in mind all the variables, wet/dry road, braking while cornering, load with rear passengers, boot, etc.?
I think I’ll set it so that it’s fully open with no rear passenger load, see if (they should) the rears lock before the fronts and then back it off from there till they’re balanced. Needs new tyres anyway!
A correctly set load compensator should be ok. You're on your own with old rear tyres or mixed front back grip levels, but only extremes of weather made a difference in my Mk2 unloaded with ancient F1 Eagle rears and UR3 fronts. Below 10 in the wet or 5 in the dry I tip-toed around roundabouts. You can get a baseline if you can find an area where you can brake like a nutter in straight lines. First test for a lack of rear bias by coasting at around 15mph+ so the car is nice and neutral then absolutely punch the brake pedal fast and hard with the aim of locking the rears in that neutral stance. Second test for rear bias you will need some speed and to brake smoothly and progressively harder to a halt. If you can't hear a rear lock you might need an observer or camera setup and perhaps a line of masking tape across the middle of the wheels. The ultimate test for the latter is under skid pan conditions on a deserted no lights roundabout with a diameter of 200ft or greater. Fast enough for a bit of body roll and the same smooth progressive braking to a halt. If the rear steps out as it lifts/pitches you have too much. Tyres have to be right or at least best set on the back.
All sounds like good advice. Don’t worry my rear tyres, in fact all 4 are Michelin exalto’s which have only done about 2000 miles. So all have like new tread on them, only problem is that because I have hardly driven the car since fitting they’re starting to crack on the walls so will need replacing. I was really annoyed actually cos could see on the date code on the wall that they were a couple of years old even when brand new on the car. Oh well! Had a closer look at the compensator and how I’d provisionally set it up when reassembling the rear beam and I only set the linkage halfway in the range of adjustment that’s available. So I’ve tightened it up about 3/4 of the way now which should make a difference, hopefully opening up the rear calipers more. While I was there however I did notice a brake fluid leak on the compensator, can’t be bad as master cyl reservoir level hasn’t dropped any but I guess the next step before going any further is to get a new compensator and then take it from there. Cheers.
Sorry I've missed the simplest advice which is to set the spring with a bit of tension, but not so much that you're fighting it whilst tightening it. Michelins do seem to be prone to cracking. I used to love it when you could order tyres direct from sites like mytyres and they would only be months old, but now if they don't go direct to the fitters they either refuse to fit or charge 2/3rds more for the fitting. My last experience with tyre fitters wasn't great and could of been fatal.
