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I agree about it being normal, but some cars are more susceptible than others - I used to notice it particularly on my 3-series. It can be quite worrying, especially at the first stop after a 100-mile motorway blast in heavy rain.
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I have had a similar thing happen to me twice with 2 different cars but this was in the dry.
One a Rover Metro & the second time a Pug 405.
Both times I managed to drive 92 miles down the motorway without ever touching the brake pedal, Both times I came off at the slip road & pressed the brake pedal & it went to the floor.
On the second application of the pedal it was normal again, Both cars where checked over & no fault was ever found with either of them, Must have been something to do with the servo & not using the brakes for all those miles.
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Thanks for all the replies everyone - very helpful.
At least I now know that this doesn't remotely count as "normal"! Saab forum search reveals nothing either. Having driven and fixed a lot of cars over the years, I have never come across this, so it was a bit of a surprise...
Given that pedal feel / travel is unaffected, my money is on the old, polished and hardened pads theory. The car had a full service last month, and new front tyres last week, so I had a good look at the front discs. Everything looked in order to me, with relatively little wear to the discs.
New pads this weekend I think, and see what happens. Good job I found out about this and not the gf! Thanks again everyone.
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I drove through a large puddle about 6" deep this morning. It made absolutely no difference to the braking effect.
A single puddle is not likely to wet the discs.
The road was flooded for a distance of about 30 feet. I judged the depth by the fact that it sent a slosh up the doors. I can't image a way of getting the disks any wetter, other than driving off a pier head.
My point was that wet disks don't in my experience have much effect on braking capacity.
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I had this with my Peugeot 309 SRi. I experienced this a few times. The wife found it once.
I never got to the bottom of the problem. The car was written off in the end, not because of that though.
H
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AN Other i agree with the men who said old pads you have said you will change them good, but make sure you only purchase o.e. pads as there are a lot of cheap pads about that are a waste of money.
With regard the other poster with his peUgEot/metro and the pedal hitting the medal i suggest the fluid had temporarily boiled in the calipers.
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\"a little man in a big world/\"
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Oldman (once again) is the voice of reason. Get a decent set of pads on it.
I bought a set of 'Nippon Braking Co.' pads from a local factor (to fit a Jap car). Expected them to be made in Japan. The damn things were made in India. Went straight back!
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Oldman, How could the fluid have boiled? I hadnt touched the brakes for 92 miles both times in both the cars so the fluid wouldnt be hot.
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The other thing is, if the brakes worked on the second pump, as they did, then foamy fluid can't have been the problem.
Much more likely the wavy discs suggested earlier, knocking the pads back, perhaps or even probably exacerbated by worn wheel bearings that the driver might have got used to, bit too much end float somehow.
At any speed at all the gyroscopic effect would sort of centre the wheels so the driver could live with the condition, unless very bad of course.
Can of worms isn't in it the moment you pick up a spanner. I've come across wheel bearings that had worn in such a way that the correct adjustment didn't stop the wheel from wobbling a bit, rounded rollers or something. Cars with that kind of wear are often perfectly driveable, many people wouldn't notice anything amiss.
Solution is replacement with new. Cars are expensive despite all we can do to make them... er... affordable.
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"Much more likely the wavy discs suggested earlier, knocking the pads back, "
But only wavy WET discs! How does that work?
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"Much more likely the wavy discs suggested earlier, knocking the pads back, " But only wavy WET discs! How does that work?
Sorry grnicol, there's a confusion here which is my fault. My post was in response to the one about driving 90 miles up the motorway without touching the brakes, then the pedal going once down to the floor, but working on the second pump in a normal manner. Not to do with the OP whose symptoms were different.
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Ahhh, no probs Lud, Thought I had totally lost the plot for a moment :-) Understand your post totally now.
For the record, I have found all my 3 series (E46) prone to unresponsive brakes (when initially applied) after a 40+ mile M-way drive in driving (pun unintended) rain, but they do work a few seconds later ;-) I do try and dry mine off with very light braking when there's no-one around that would be affected (not easy!) and obviously I widen the standard following position from BMW approved 0.5 ms gap to about 4 seconds (also not easy to do - but safety has to come first of course)....having said that maintaining 2 secs is hard enough without inviting interlopers/undertakers. I must try and get some "battenburg" yellow/blue checks for my car to keep the rebels at bay :) I'm darn sure I have a huge magnet in the boot, but I haven't found it yet!
Thanks again for the clarification Lud.
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so the front pads/discs were perfect then and no kinetic energy between disc/pad caliper?your brake pedal couldnt hit the floor then?could it
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\"a little man in a big world/\"
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sorry last post to powerlee
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\"a little man in a big world/\"
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My point was that wet disks don't in my experience have much effect on braking capacity.
It probably depends on the car model. Some cars may be more prone than others to the discs getting wet. My Focus manual says "Wet brake discs result in reduced braking efficiency." I have experienced the problem a few times in my lifetime, but certainly not regularly ~ usually after a carwash or after driving a long distance without using the brakes on a wet motorway.
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L\'escargot.
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Master cylinder seals have been know to cause it by folding back on themselves while braking harder than usual,then under normal braking it wont happen again,Untill you need to do emergency stop and nothing happens apart from pedal hits the floor.
then on pedal return brakes are fine
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Steve
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AN,
Have new pads solved the problem? I know of another experience 100 miles of motorway driving (not raining) come to a slip road no brakes !!!! astra 1.4 N Reg, 4 miles later OK, taken to a garage they had it on ramps, test drove it, no problems. I thought it might be master cylinder ?
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There was a problem with Astras of about this age with water getting into the brake fluid - do a forum search.
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pmh (was peter)
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Thought I'd better post an update.
Changed pads for genuine Saab pads a couple of weeks ago. De-glazed, de-greased and cleaned up the discs while I was at it, as well as making sure the calipers slid freely. Brake grease applied to bits that needed it.
Result= problem solved. I've now been in several situations which would previously have caused a problem, and the brakes are more positive and powerful than before, with no scary moments.
Thanks again to all for advice. For the record, the pads which came off were less than half worn, and visibly OK, with no obvious contamination or degrading. They didn't bleeding work, though!
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Stick them in a hot oven for 30 minutes, might burn off whatever's contaminated them. Worked on the pads for my bike after a bottle of DOT 5.1 exploded in my toolbox.
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Something along the lines of the original post happened to me a few weeks ago. Driving hundered of miles (Lutterworth to Glenrothes) with the A1 route in driving snow, slush on the road that was also heavily gritted and no real need to apply the brakes for many miles...when I did use them it took a few seconds for them to really engage.
I think that there needs to be something other than just water to seriously affect brakeing performance, namely, debris or salt or grit etcetera. This is what will take time to burn through by the pad and disk. If it has not rained for some time then a lot of debris is thrown up and sprayed/splashed by the one wheel onto the other wheel.
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Any evidence of the manufacturer's name or mark on the pads you removed?
659.
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Good question. I did check, but couldn't find anything. They looked outwardly like the OE ones I replced them with. I suspect that the previous owner had his local garage fit them, so they would have been whatever the factors came up with.
Interestingly, there was actually a recall on very early GM900s, to fit a modified disc backing plate to cure just this problem. I checked with Saab, but mine was not affected. However, there were a lot of recalls! Might be worth a good check through these if you've got an older car. Plenty of sites will give this info, but www.automotive.com/used-cars/recalls/ isn't a bad place to start.
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