Kia Rio - Low Biting Point and Notchy Gear Changes
Discussion
Evening all, don't suppose someone a bit more experienced could help me in this area. I've just bought a Kia Rio today and although I noticed the biting point was virtually near enough the bottom of the pedal travel I hadn't happened to notice that the gear change was quite notchy as I've had a few cars like this myself in the past which are known for it, however I'm not sure the Kia Rio is known for this as this is the only one I've ever driven! 
A couple times along the long drive home I had trouble getting it in to first, where it felt as if the clutch wasn't fully disengaged as when trying to put it in to first it would feel as if the car was trying to pull forward (as if the clutch pedal wasn't depressed). When the clutch was pressed again it was easier to get in to gear.
Would you recommend having a general look at everything first and then trying to bleed the clutch or are these cars simply known for having a notchy gearbox/low biting point?
A couple times along the long drive home I had trouble getting it in to first, where it felt as if the clutch wasn't fully disengaged as when trying to put it in to first it would feel as if the car was trying to pull forward (as if the clutch pedal wasn't depressed). When the clutch was pressed again it was easier to get in to gear.
Would you recommend having a general look at everything first and then trying to bleed the clutch or are these cars simply known for having a notchy gearbox/low biting point?
Seems to me that you have a fault in the clutch release mechanism. It's probably hydraulic and if so should be reasonably straight forward to diagnose. Check the fluid level, try flushing the fluid to see if that helps, otherwise you're looking for a cylinder fault. If the slave cylinder is leaking, that's the problem. Otherwise, the problem is probably at the master cylinder end of things.
If you keep driving it with the clutch not disengaging fully you will wear the gearbox synchros prematurely.
If you keep driving it with the clutch not disengaging fully you will wear the gearbox synchros prematurely.
Cheers guys. Well I'm not happy to say but it seems as though I've made the problem 100 times worse. I had a quick inspection of both master and slave cylinders to fine no evidence of leaking however the fluid was looking worse for wear (dark brown), so I decided to flush and bleed the system.
I started off by sucking the old fluid out of the reservoir and topping up with new stuff and had my girlfriend push the pedal down as I opened the bleed nipple on the slave cylinder, then closing it and having her let the pedal back up... the pedal didn't come back up. Since I've put half a litre of fluid through it, but air seems to be getting in from somewhere... any ideas before I call in a mobile mechanic?
I'd love to take it to a dealer however the warranty has long since expired (some 8 years ago).
I started off by sucking the old fluid out of the reservoir and topping up with new stuff and had my girlfriend push the pedal down as I opened the bleed nipple on the slave cylinder, then closing it and having her let the pedal back up... the pedal didn't come back up. Since I've put half a litre of fluid through it, but air seems to be getting in from somewhere... any ideas before I call in a mobile mechanic?
I'd love to take it to a dealer however the warranty has long since expired (some 8 years ago).
I don't know how much experience you have with hydraulics but there's a knack to bleeding using that approach. You need to close the bleed valve during the pressure stroke and not wait until the end of the stroke - otherwise you just suck air back every time. A technique that I find very effective is to take a hose from the bleed nipple back up to a jar next to the reservoir so you can see the quality of fluid coming out and whether there is any air in it. Bringing the hose up puts the connection to the bleed nipple under very slight pressure which avoids air being drawn in, and if the system is basically intact you can keep flushing fluid through without opening and closing the bleed nipple until you're happy it's working.
It was the slave cylinder that had gone on my Rio when the clutch stopped working. I can't remember if it was actually leaking externally. I just bought a new one on Ebay for not much money and stuck it in. It's far more likely to be slave than master that's failed on most hydraulic systems. Like yours it got tetchy and low disengaging point for a short while and then total failure which made for an interesting drive home, especially at junctions.
GreenV8S said:
I don't know how much experience you have with hydraulics but there's a knack to bleeding using that approach. You need to close the bleed valve during the pressure stroke and not wait until the end of the stroke - otherwise you just suck air back every time. A technique that I find very effective is to take a hose from the bleed nipple back up to a jar next to the reservoir so you can see the quality of fluid coming out and whether there is any air in it. Bringing the hose up puts the connection to the bleed nipple under very slight pressure which avoids air being drawn in, and if the system is basically intact you can keep flushing fluid through without opening and closing the bleed nipple until you're happy it's working.
Thanks, I'll try that technique, assuming the system currently has a lot of air in it how long do you think this will take? Not sure if the master or slave is faulty, the only reason I bled it in the first place was because the biting point was virtually very close to the floor and the clutch seemed to be barely disengaging.
TehRin said:
Thanks, I'll try that technique, assuming the system currently has a lot of air in it how long do you think this will take?
About five minutes and half a liter of fluid should flush the system through thoroughly including any air that has got in. If you do it correctly, this should be a quick job. GreenV8S said:
About five minutes and half a liter of fluid should flush the system through thoroughly including any air that has got in. If you do it correctly, this should be a quick job.
Assuming I'm doing it correctly and nothings f
d. I have a feeling air was finding it's way in around the thread of the bleed nipple, this time I'll only crack it 1/8th of a turn.E-bmw said:
With pressure behind the fluid it is pretty much impossible for air to get pulled in through the bleed nipple threads.
That ^^If you do it correctly you will have pressure on the pedal the whole time from when you open the bleed nipple to when you close it. You may get a trace of fluid leaking out past the thread but there will never be any chance for air to leak in.
Or use the technique I suggested of connecting a hose from the bleed nipple up to a catch bottle up near the master cylinder; that's another way of keeping a slight positive pressure on that lets you bleed the brakes single handedly without having to mess around so much with the bleed nipple.
Right, tried again using the said method with no success. I have a feeling the master cylinder is faulty, as I open ended the pressure end, had someone push the pedal down slowly, and only towards the end of the pedal moving did any fluid come out. Then with the pedal fully down I put my gloved thumb over the end, had the other person pull up the pedal (slowly) and although it took in a tiny bit of fluid from the reservoir, on the downward stoke it was all air again, only towards the end did it pump a little bit of fluid.
Now, I would have thought that with my thumb firmly over the pressure end of the master cylinder that on the upward stroke of the pedal it would take in fluid from the reservoir, not fill up with air.
Also, when I was pumping the pedal by hand using the jar method I could hear noise coming from the slave on the upward pedal stroke, not a hiss, more like click which would continue for a few seconds after the pedal was fully up.
Is it possible a problem with the master cylinder would only appear when trying to bleed the system?
Now, I would have thought that with my thumb firmly over the pressure end of the master cylinder that on the upward stroke of the pedal it would take in fluid from the reservoir, not fill up with air.
Also, when I was pumping the pedal by hand using the jar method I could hear noise coming from the slave on the upward pedal stroke, not a hiss, more like click which would continue for a few seconds after the pedal was fully up.
Is it possible a problem with the master cylinder would only appear when trying to bleed the system?
GreenV8S said:
Pulling *up* on the pedal? What on earth's that about?
Is there a problem with the clutch return spring?
The pedal is dropping so low because of the lack of fluid in the master cylinder I think... however I have to pull the pedal back up as it drops right to the floor, but when being pulled back up I can then feel a spring that then holds it up. It's as if when it drops past a certain point the spring has no effect because of the angle it's probably sitting at. I'm awful at explaining things like this, however the pedal definitely has spring assistance in it's normal moving range.Is there a problem with the clutch return spring?
Now about the master cylinder, do you think with the outlet blocked up it should have drawn in fluid on the upward stroke of the pedal? I'm going to test it tomorrow by putting a plug in it, I've got a few BSP sizes, not sure of the thread size though, probably isn't BSP.
I'll do a test with the outlet blocked on the upward stroke and then the downward stroke.
If the master cylinder was working correctly you'd assume that:
On the upward stoke with a blocked outlet it would draw fluid from the reservoir.
On the downward stroke with a blocked outlet it would feel springy or have a high resistance on the pedal whether it was filled with air/fluid or a mix of both.
Is that correct?
The spring may have some clever setup to make it less effective at the bottom of the travel, but it ought to put at least some tension on the pedal throughout the whole travel. Bear in mind that it's perfectly normal for the clutch pedal to be pushed down to the carpet.
The behaviour you describe with the outlet blocked off is not quite right. The master cylinder will only open the port to the reservoir at the very top of the stroke. At any other position, if you block off all the outlets from the m/c then the pushrod should go solid, and the only movement you get will correspond to air inside the m/c being compressed or expanded.
The behaviour you describe with the outlet blocked off is not quite right. The master cylinder will only open the port to the reservoir at the very top of the stroke. At any other position, if you block off all the outlets from the m/c then the pushrod should go solid, and the only movement you get will correspond to air inside the m/c being compressed or expanded.
GreenV8S said:
The spring may have some clever setup to make it less effective at the bottom of the travel, but it ought to put at least some tension on the pedal throughout the whole travel. Bear in mind that it's perfectly normal for the clutch pedal to be pushed down to the carpet.
The behaviour you describe with the outlet blocked off is not quite right. The master cylinder will only open the port to the reservoir at the very top of the stroke. At any other position, if you block off all the outlets from the m/c then the pushrod should go solid, and the only movement you get will correspond to air inside the m/c being compressed or expanded.
I'll take another look at the spring today, and see what's going on.The behaviour you describe with the outlet blocked off is not quite right. The master cylinder will only open the port to the reservoir at the very top of the stroke. At any other position, if you block off all the outlets from the m/c then the pushrod should go solid, and the only movement you get will correspond to air inside the m/c being compressed or expanded.
Okay, so with the outlet blocked I should feel more resistance in the pedal? Because what I'll be doing is trying to compress or expand whatever is in there, so if it behaves in the exact same way whatever is in there is passing by the piston?
It sounds like you COULD have 2 issues so work with 1 at a time.
When you describe bleeding from yesterday did you just do it a few times or repeatedly?
What you say about a gloved finger will work in most cases but stick with the proper procedure for now.
FULL reservoir. (I say FULL as many use the brake reservoir with a weir between the 2 pick-ups and can appear to have plenty in but the clutch side can be empty)
Foot on pedal with light pressure.
Open bleed.
Close before pedal to the bottom
Return pedal to the top (Lift pedal if you have to) with bleed nipple closed.
Repeat around 20 times making sure to check the reservoir level does not drop.
Then report back.
When you describe bleeding from yesterday did you just do it a few times or repeatedly?
What you say about a gloved finger will work in most cases but stick with the proper procedure for now.
FULL reservoir. (I say FULL as many use the brake reservoir with a weir between the 2 pick-ups and can appear to have plenty in but the clutch side can be empty)
Foot on pedal with light pressure.
Open bleed.
Close before pedal to the bottom
Return pedal to the top (Lift pedal if you have to) with bleed nipple closed.
Repeat around 20 times making sure to check the reservoir level does not drop.
Then report back.
E-bmw said:
It sounds like you COULD have 2 issues so work with 1 at a time.
When you describe bleeding from yesterday did you just do it a few times or repeatedly?
What you say about a gloved finger will work in most cases but stick with the proper procedure for now.
FULL reservoir. (I say FULL as many use the brake reservoir with a weir between the 2 pick-ups and can appear to have plenty in but the clutch side can be empty)
Foot on pedal with light pressure.
Open bleed.
Close before pedal to the bottom
Return pedal to the top (Lift pedal if you have to) with bleed nipple closed.
Repeat around 20 times making sure to check the reservoir level does not drop.
Then report back.
Repeatedly. Using the jar method I had the fluid being pumped all the way out of the bleed nipple, up the bonnet and to the bottle which I had placed by the reservoir, with no air bubbles in it at all. However, with each pump I could see I was pumping less liquid, so as the pressure went up slightly it's possible the master cylinder was pumping less due to the fluid passing around the piston in it or air in the system. When you describe bleeding from yesterday did you just do it a few times or repeatedly?
What you say about a gloved finger will work in most cases but stick with the proper procedure for now.
FULL reservoir. (I say FULL as many use the brake reservoir with a weir between the 2 pick-ups and can appear to have plenty in but the clutch side can be empty)
Foot on pedal with light pressure.
Open bleed.
Close before pedal to the bottom
Return pedal to the top (Lift pedal if you have to) with bleed nipple closed.
Repeat around 20 times making sure to check the reservoir level does not drop.
Then report back.
I've tried that bleed method, gravity bleeding (leaving it for 30 mins with the nipple cracked before bleeding), the jar method, and the Vizibleed kit.
The car is still under a dealer warranty so I may just take it back.
This is very simples. Remove the line to the slave cylinder and block it off with a plug. The pedal should be firm and not sink when held under steady pressure. If it sinks then fluid is leaking back past the plunger seal. Even if there's some air in there and the pedal is a bit spongy (it should self bleed) it should still hold position under steady pressure. If the pedal stays firm then it's the slave cylinder at fault. If not it's the master.
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