Definitive AU1 to AU2/AU3 brake upgrade thread

[lumen8]

Originally Posted by Ben

So I am looking at getting RBS to sort out the fronts for me so I can put them on when I do the calipers. And from what I have read I can make my current rears just work with the terry calipers so I can get my car to one of these shops to make up the rears.

Yes they can work, ive put terry rear brakes on an IRS AU with factory rear lines... a 4 channel ABS car, so the rear has its own brake line running along each side of the chassis and to the caliper. (AU fairlane)

The rears if I remember right were the same deal as what i said about the front AU lines earlier, i milled some material off one corner of the block that bolts to the caliper so i could turn/orientate the block and line correctly as it comes off the caliper. Because the notch in the terry caliper around where the brake line bolt lives is a bit different to the AU.

I havent read the entire thread so I dont know what others have said or done regarding using the stock AU rear brake hoses on the terry calipers, but I took some metal off the side of the block to get them sitting how i felt was right.

I just did it with a bench grinder (removed rubber line from car first obviously) and cleaned it all up afterwards etc. before refitting. Flushed and bled the brakes well, rock hard pedal was the result and no problems. Would be even better with new SS lines of course.

[lumen8]

So I did some work on someones 99 AU Fairlane recently, september 99 build series 1.

Owner wanted to upgrade to AU2 master cylinder and booster and eventually the 322mm/328mm deal.

Did the MC and booster first, series 2 stuff... bolted in a series 2 pedal box and redrilled firewall using the 4 pedal box holes as a guide. The pedal boxes are the same except the series 2 box has the 4 holes versus the 2 for series 1, and none of the holes are in the same place...so I figure its easier to bolt the series 2 pedal box in and then drilling the holes in the correct place is much easier.

I was able to drill all 4 of them from the interior side after punching the centre using the series 2 pedal box holes as a guide.

I had read that Ford changed the shape of the firewall where it meets the cowl panel slightly on series 2, and series 2 stuff didnt sit flat on a series 1 firewall due to interference where the firewall meets the cowl panel (join was lower on series 1s and hits the series 2 booster) , and some minor panel beating could rectify that.

then someone somewhere said a Feb 2000 series 1 had the updated shape and the booster went straight in no probs.

Well on this september 99 car same thing, just drilled the 4 holes the series 2 booster needed and no interference, its sitting flat and vertical on the firewall.

So i bled the brakes with the series 2 master and booster and the car stops much better even with the series 1 front brakes still on it. (rears are the same caliper piston between 1 and 2 essentially, discs just thinner on the 1)

So this is the other way around to what some have done where they install series 2 brakes and leave the series 1 booster and master cylinder.

The series 1 booster is plastic and ive found it to flex a great deal, not very good.

This car will get the bigger brakes eventually but i found it interesting that the series 2 stuff with its steel booster that doesnt flex and the bigger bore MC resulted in greatly improved braking.

Im not sure there is much talk of fitting the series 2 booster and MC in this thread without needing wedge plates and the like, and doing this with the series 1 brakes still in place, hence my post and bump here for improving these old rides without too many dramas lol.

[jimmo]

Sweet!! Thanks for the info, mate, that's a big help as I was wondering what I was going to do. I just checked my series 1 project and its an Oct 99 build! Will now do the same MC/Booster upgrade and add a 322/328 setup off a BF turbo. Cheers..

[ebv8]

if i was doing it again i'd go the S2 booster just for the daily driving and using light brake pressure.
i found the S1 booster on 322/328 brakes didn't make the brakes worse but it needed more foot pressure, still worked great on the track though just not ideal on the road for lazy driving
i also put my old S1 brakes on the S2 doner car and that was almost undrivable, the brakes were extremely touchy as it was over boosted but it can be done

[lumen8]

Originally Posted by ebv8

if i was doing it again i'd go the S2 booster just for the daily driving and using light brake pressure.
i found the S1 booster on 322/328 brakes didn't make the brakes worse but it needed more foot pressure, still worked great on the track though just not ideal on the road for lazy driving
i also put my old S1 brakes on the S2 doner car and that was almost undrivable, the brakes were extremely touchy as it was over boosted but it can be done

Probably because the initial foot effort is taken up in flex. If you get someone to push the brakes while watching the boosters plastic vs metal you would see a difference between the two.

So you put S1 brakes on a S2 car with the S2 booster and MC?

I didnt find this car to be too touchy actually, I drove it a fair bit. It suprised me and the owner actually as to how much better it pulled up, and it wasnt just the initial feel with less foot pressure applied ..(which is better with the S2 booster as you said). I did a few hard emergency braking stops even from high speeds... it did have ABS though so couldnt lock the brakes if i tried.

but i guess adding more pressure to existing calipers is nothing new... hydroboost conversions are another example where that applies.


Unrelated but has anyone tried those new protex brand MC's ? Lots of them all over fleabay and theyre available from auto stores.

I tried a new one on my own Fairlane and could not get it to work.. ended up returning it. The brake pedal would lock up halfway through its movement and couldnt get fluid out of the calipers. And im not inexperienced at bleeding brakes, I was a tech at a dealership even once upon. Tried everything including of course bench bleeding it first.. something was off about it inside, and i didnt care to spend the time to pull it apart and compare to an OEM pbr master cylinder.