I have recently acquire a 1991 AX GT. The brakes when I got it were awful...improved substantially with brake bleeding, lots and lots of air came out. After about 2 litres of brake fluid went through, no air bubbles. The pedal was still a bit spongy. After sitting for a month or so the brakes are again quite spongy and not stopping the car well. I can find no signs of leakage at front discs, rear slave cylinders or master cylinder.
I am told the brakes on AXs are always pretty bad. There are only about 14 of them in Australia, so not much knowledge here.
So: can anyone suggest what might be wrong with my AX's brakes? And are the brakes always poor? If so, what modifications can be made to provide decent braking?
AX GT brake problem
Moderator: RichardW
Brakes are not supposed to be poor on an AX.
The AX brake system is of conventional design and construction. Like any other small car you have down there. Nothing special as found on the larger hydropneumatic Citroens.
If the brake pedal can be pumped - you have a problem with the master cylinder seals.
You are absolutely sure the brakes fluid reservoir level is not sinking over time - indicating a leak somewhere ?
That would be about the only plausible explanation for air getting into the brake piping.
Note that over time when pads/disks are worn - the caliper pistons will move out further to compensate. This in turn causes more brake fluid to stay in the caliper cavity.
The AX brake system is of conventional design and construction. Like any other small car you have down there. Nothing special as found on the larger hydropneumatic Citroens.
If the brake pedal can be pumped - you have a problem with the master cylinder seals.
You are absolutely sure the brakes fluid reservoir level is not sinking over time - indicating a leak somewhere ?
That would be about the only plausible explanation for air getting into the brake piping.
Note that over time when pads/disks are worn - the caliper pistons will move out further to compensate. This in turn causes more brake fluid to stay in the caliper cavity.
Anders (DK) - '90 BX16Image
I agree with Anders. Air can't just get in to braking systems and a likely culprit is the master cylinder seals. On old unservo'd systems it was common to find fluid dribbling down the brake pedal but with direct acting servo units behind the brake master cylinder the fluid dribbles into the servo instead.
Take the master cylinder apart and you'll probably find the seals are like wine gums! - soft and spongy with no sharp edges left.
Take the master cylinder apart and you'll probably find the seals are like wine gums! - soft and spongy with no sharp edges left.
jeremy
AX brakes saga - solution?
Thanks for the feedback guys, I'm grateful. The saga continued...hopefully to a happy conclusion!
While the master cylinder showed no signs of leaking into the brake booster, I pulled it apart. The seals on the outer piston looked a bit round shouldered, so I took the master cylinder to my friendly local brake place to have a new kit installed.
On reinstalling the M/C, I bled three quarters of a litre of brake fluid through before all the small bubbles seemed to have disappeared. But the brake pedal still had a lot of travel, and was a bit spongy, harder on repeated pumping.
I had already established that the rear brake shoes are reasonably well adjusted - no excessive travel on the handbrake. Front discs, of course, are self adjusting.
On right hand drive AXs, as used in Australia and UK, the booster is on the left. There is a threaded rod connecting the pedal assembly on the right to the rear of the booster on the left. This has an adjustment over the brake pedal, accessible in front of the firewall- I used this to effectively shorten the rod by about 20mm. This improved the pedal greatly - much less travel before the brakes start to bite. The sponginess seems to have diminished, and may be within normal limits. I am not sure if the brakes are 100%, but they are much better and at least 80 to 90% of what I would expect. On heavy braking at least one wheel is locking.
This leads me to wonder whether problems with AX brakes in UK and Australia may be due to the rod linkage. The fulcrum/anchoring point for this is a bracket on the right hand side. The bracket is made of fairly light weight sheet metal. I wonder if this bends slighly over time, creating excessive travel in the brake travel, and hence the need I had to adjusting the rod to shorten it?
Worth a look for those people with right hand drive AXs who have excessive brake travel, but properly adjusted rear brakes.
While the master cylinder showed no signs of leaking into the brake booster, I pulled it apart. The seals on the outer piston looked a bit round shouldered, so I took the master cylinder to my friendly local brake place to have a new kit installed.
On reinstalling the M/C, I bled three quarters of a litre of brake fluid through before all the small bubbles seemed to have disappeared. But the brake pedal still had a lot of travel, and was a bit spongy, harder on repeated pumping.
I had already established that the rear brake shoes are reasonably well adjusted - no excessive travel on the handbrake. Front discs, of course, are self adjusting.
On right hand drive AXs, as used in Australia and UK, the booster is on the left. There is a threaded rod connecting the pedal assembly on the right to the rear of the booster on the left. This has an adjustment over the brake pedal, accessible in front of the firewall- I used this to effectively shorten the rod by about 20mm. This improved the pedal greatly - much less travel before the brakes start to bite. The sponginess seems to have diminished, and may be within normal limits. I am not sure if the brakes are 100%, but they are much better and at least 80 to 90% of what I would expect. On heavy braking at least one wheel is locking.
This leads me to wonder whether problems with AX brakes in UK and Australia may be due to the rod linkage. The fulcrum/anchoring point for this is a bracket on the right hand side. The bracket is made of fairly light weight sheet metal. I wonder if this bends slighly over time, creating excessive travel in the brake travel, and hence the need I had to adjusting the rod to shorten it?
Worth a look for those people with right hand drive AXs who have excessive brake travel, but properly adjusted rear brakes.
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Stinkwheel
- Posts: 562
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When i was running AX GT's i also found the brakes to be pretty poor compared to the performance of the car.
I had troubles with rear wheel cyclinders as well, if the car was left these would partially seize up.
The pedals on both my old GT's were a little spongy, not soft or needing a pump just a little mushy feeling. I dont believe there was anything wrong though.
Great little cars, in fact i may go e-baying in a moment
I had troubles with rear wheel cyclinders as well, if the car was left these would partially seize up.
The pedals on both my old GT's were a little spongy, not soft or needing a pump just a little mushy feeling. I dont believe there was anything wrong though.
Great little cars, in fact i may go e-baying in a moment
"Rust Never Sleeps" said Neil Young. Did he own old citroens?
1998 Xantia TD exclusive auto estate +3 x BX's +77' ami 8 break + 73' dyane 6 + '83 2CV6 + 94' XM 2.1 sx auto + 89' XM2.0i
+ '85' GSA + '97 XM 2.0 16v + '81 Visa super E
1998 Xantia TD exclusive auto estate +3 x BX's +77' ami 8 break + 73' dyane 6 + '83 2CV6 + 94' XM 2.1 sx auto + 89' XM2.0i
+ '85' GSA + '97 XM 2.0 16v + '81 Visa super E
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Stinkwheel
- Posts: 562
- Joined: 28 May 2004, 01:02
- Location:
- My Cars:
- x 1
how much? id love too but i think its a little out of my range at the minute
"Rust Never Sleeps" said Neil Young. Did he own old citroens?
1998 Xantia TD exclusive auto estate +3 x BX's +77' ami 8 break + 73' dyane 6 + '83 2CV6 + 94' XM 2.1 sx auto + 89' XM2.0i
+ '85' GSA + '97 XM 2.0 16v + '81 Visa super E
1998 Xantia TD exclusive auto estate +3 x BX's +77' ami 8 break + 73' dyane 6 + '83 2CV6 + 94' XM 2.1 sx auto + 89' XM2.0i
+ '85' GSA + '97 XM 2.0 16v + '81 Visa super E