Exciting weekend of autocrossing - cooling issues and brake problem to diagnose
06-13-2011, 09:29 PM
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Exciting weekend of autocrossing - cooling issues and brake problem to diagnose
Well, I had an exciting weekend of autocrossing!
On Saturday, during my fourth and final run, my fan cut a hole through the upper radiator hose. I crossed the line and the guy handing out timing slips told me my brakes were on fire!
I pulled over in the grid and set up shop. One guy told me he'd seen a part fall off the car at the far end of the course. Several people told me my left front brake rotor was on fire.
http://www.youtube.com/watch?v=ON_8VqNDoZY
Since it was pretty obvious I had had a coolant leak, I figured I'd fix that first and then worry about the brakes, if necessary.
Coolant was EVERYWHERE!
I took off the airbox and with some poking around, discovered that the upper radiator hose had gotten chewed up by the fan blade. I got a ride over to Advance Auto which, not surprisingly, did not stock an upper radiator hose for a 1986 944 Turbo. In case you're not familiar, this hose has one diameter at one end, a different diameter at the other, and two 90 degree bends. I managed to find two hoses with the correct diameters and the correct bends. The miracle was, I found an exhaust adapter with the correct diameters that I could cut the two hoses at the right points and join them with the exhaust adapter and some hose clamps. Drove back to the lot, and a couple of hours later the car was running!
So, I was pretty convinced that the brakes were fine because there was plenty of evidence that coolant had made its way into the wheel and brake area, and that lots of steam was produced. The car drove fine on the way to the hotel, and I tested the brakes with no change to their performance from before.
So, the improvised upper radiator hose held fine the next day, and even got me home (150 miles)!
But let's revisit the brakes. I'll back up. At my last track event, December, my brake booster failed. I fixed it over the winter, and replaced the brake m/c and clutch m/c at the same time. (This was a bitch, by the way).
The pedal was subsequently a bit softer than it had been prior to the brake booster failure, but I knew I wouldn't be getting to any events until June, and I still had a plan to replace the calipers, so I didn't worry if there might have been a bubble or two in the lines somewhere.
So, last week, I finally got a chance to replace the brake calipers with newly rebuilt calipers. I bled them three times and by the time I was done, the brakes were just like they had been ever since I had replaced the brake booster-- reasonably good, but certainly not firm the way they had been in the past. I resigned myself to believing that they were firm enough, that perhaps there was just a little more pedal play than there had been before.
Over the weekend, I ran four times on Saturday. Brakes were slightly soft, just as they had been. I then experienced the coolant issue. Drove the car to the motel and the brakes were the same. Woke up, drove back to the lot, and the brakes were the smae. I ran four times on Sunday, the brakes were the same.
Then, I let my step-son drive. Let's just say, politely, that he is hard on equipment. In his final run, he came across the line sideways, hit the brakes, and took out a wall of cones is we spun.
OK, I expected that my tires would have some flat spots. But here's the interesting thing: now, my brake pedal is hard like it used to be before the brake booster problem! However, now, it has a slight pull to the left under braking.
What explains this???
On Saturday, during my fourth and final run, my fan cut a hole through the upper radiator hose. I crossed the line and the guy handing out timing slips told me my brakes were on fire!
I pulled over in the grid and set up shop. One guy told me he'd seen a part fall off the car at the far end of the course. Several people told me my left front brake rotor was on fire.
http://www.youtube.com/watch?v=ON_8VqNDoZY
Since it was pretty obvious I had had a coolant leak, I figured I'd fix that first and then worry about the brakes, if necessary.
Coolant was EVERYWHERE!
I took off the airbox and with some poking around, discovered that the upper radiator hose had gotten chewed up by the fan blade. I got a ride over to Advance Auto which, not surprisingly, did not stock an upper radiator hose for a 1986 944 Turbo. In case you're not familiar, this hose has one diameter at one end, a different diameter at the other, and two 90 degree bends. I managed to find two hoses with the correct diameters and the correct bends. The miracle was, I found an exhaust adapter with the correct diameters that I could cut the two hoses at the right points and join them with the exhaust adapter and some hose clamps. Drove back to the lot, and a couple of hours later the car was running!
So, I was pretty convinced that the brakes were fine because there was plenty of evidence that coolant had made its way into the wheel and brake area, and that lots of steam was produced. The car drove fine on the way to the hotel, and I tested the brakes with no change to their performance from before.
So, the improvised upper radiator hose held fine the next day, and even got me home (150 miles)!
But let's revisit the brakes. I'll back up. At my last track event, December, my brake booster failed. I fixed it over the winter, and replaced the brake m/c and clutch m/c at the same time. (This was a bitch, by the way).
The pedal was subsequently a bit softer than it had been prior to the brake booster failure, but I knew I wouldn't be getting to any events until June, and I still had a plan to replace the calipers, so I didn't worry if there might have been a bubble or two in the lines somewhere.
So, last week, I finally got a chance to replace the brake calipers with newly rebuilt calipers. I bled them three times and by the time I was done, the brakes were just like they had been ever since I had replaced the brake booster-- reasonably good, but certainly not firm the way they had been in the past. I resigned myself to believing that they were firm enough, that perhaps there was just a little more pedal play than there had been before.
Over the weekend, I ran four times on Saturday. Brakes were slightly soft, just as they had been. I then experienced the coolant issue. Drove the car to the motel and the brakes were the same. Woke up, drove back to the lot, and the brakes were the smae. I ran four times on Sunday, the brakes were the same.
Then, I let my step-son drive. Let's just say, politely, that he is hard on equipment. In his final run, he came across the line sideways, hit the brakes, and took out a wall of cones is we spun.
OK, I expected that my tires would have some flat spots. But here's the interesting thing: now, my brake pedal is hard like it used to be before the brake booster problem! However, now, it has a slight pull to the left under braking.
What explains this???
