Lancia Delta Integrale Group B Rally Car brake problem sorted.

Published on 12 July 2023 at 18:21

Before I start on this one I must apologise for the lack of photos and video, my camera card has corrupted again and I have lost hours of vid and dozens of photos - not a happy bunny. I will probably go back tomorrow to redo some footage.


Anyway we got the car in to the garage, we had cracked open the rear brake line  to relieve the pressure so we could move the car about and start to look in to what was going on. The braking system is very different to your average road car so a bit of familiarisation seemed to be in order before conclusions were jumped to. We had a couple of theories and we already knew it was the rear circuit causing the problem, we also knew the problem was not at the pedal end, that was as far as it went.

We worked out that there were two master cylinders with a bias bar that could be adjusted from inside the car, weirdly there was a second bias adjuster in the form of a proportioning valve down near the handbrake. The hydraulic pipe from the rear master cylinder goes in to the proportioning valve and then from there in to the handbrake master cylinder, which is operated by a fly off type lever. The pipe from there goes to a splitter inside the car and then from there to each of the rear wheels.

We thought at first that maybe either the proportioning valve or the master cylinder was playing up but then the penny dropped and the solution turned out to be much more simple than we had thought. It turns out that on the handbrake lever there was a rubber band, the purpose of which was to hold up a threaded bar that drops down under gravity if it is not retained by the rubber band. It's basically to give the car a proper handbrake for use when parked up - when it is retained by the rubber ring it is used by  rally drivers with death wishes to bring the back end of the car round. Yes, it was as simple as that, the rod that I thought was a stop was causing the handbrake to come on and stay on. Oh how silly we felt LOL.

Now this rubber band, which we suspect to be a proper race developed item had been slid right back, I hadn't even seen it until Russell pointed it out. Neither of us had really had much to do with the car before, I have a few other excuses as well, which I will roll out as required.  I am glad it was nothing expensive, we now both know an awful lot more about the car than we knew on Sunday. I wish we hadn't made the assumption that it was an adjustment problem and that we had looked in to it on the day but given the value of the car we didn't want to take things to bits in the middle of a field.

We didn't bother sparing Malc's blushes and the piss was taken. He took it well, although he did say something about ritual sacrifice and / or execution so we changed the subject.

While we were at it we looked in to why the gear lever fell apart, it changes gear much better when the lever is attached to the pushrod. Somebody had put so many washers on the bolt that held the two parts together that the end wasn't reaching the nylon locking ring on the nut. I took 2 off, tightened it up, it won't come off again.

while it was up in the air Malc gave all the wheels a good clean, we decided that the front brake fluid looked really nasty so we drained the header tank, filled it with clean high temp DOT4 and bled the system through until nice, new clean fluid was coming out of both bleed nipples. The stuff that came out was proper nasty and had clearly been well overheated at some time, probably in the dessert rally it last competed in. There is a video on youtube, I believe one of the cars in it is the one Malc now owns, albeit a bit changed from where it was prepared for dessert stages - it can be found here - I will try and confirm it's the same car, Malc will probably know for sure.

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