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Matt, Mechanical Engineer
Category: UK Car
Satisfied Customers: 21599
Experience:  BEng hons Mech engineering, in auto industry 22 years
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I have an early 2004 hyundai Tucson CRDi 4WD. Only owned it

Customer Question

Hi, i have an early 2004 hyundai Tucson CRDi 4WD. Only owned it for 3 months, but a constant issue with severe low clutch bite and spongy brakes. There is a receipy for gear linkage and new Slave cylinder, but I've bought a genuine clutch Master cylinder too, to no effect.
It has occured to me that in 2005 the clutch master cylinder was replaced entirely on this model This leads me to believe they were a defective unit and replced across the model.
So, firstly i'd like to know if this hydraulic system does have inherent faults from 2004?
I can smell brake fluid, but there is no sign of a leak from either master or slave cylinder, however, I have not been inside the bell housing to for leaks there.
I'm about ready to scrap it as it's becoming increasingly difficult to engage gear or brake effectively, especially when cold.
The system ws beld thru the slave cylinder when the Master was replaced, but no realise there is a correct procedure to bleed this vehicle which i have not yet found.
Can you help?
Submitted: 1 year ago.
Category: UK Car
Expert:  Matt replied 1 year ago.


I'd double check all the unions for tightness on all the joints 1st
Also I'd use a pressure bleeder such as Easibleed to push fluid through to each corner first then use the two person method below to bleed the brakes and clutch

I favour having a clear hose from the nipple to a jar 1/2 full of old fluid and with the nipple closed your assistant pushes the pedal up and down a few times then holds it down then you crack open the nipple and close it again whilst fluid is still flowing.

Repeat this a few times on all calipers and start with the caliper furthest away from the master cylinder.

If you still have an issue then it could be a flexible brake line is ballooning under pressure, this can't always be seen from the outside so to test this use a hose clamp on each line in turn to close off then lines one at time . Push the pedal in between and see if you can feel any difference as each line is closed off.

Customer: replied 1 year ago.
Hi, Matt, thank you for your reply. I actully know all of this, plus my close friend is a mechanic of 30 years now. We have tried everything you have suggested, but my question was to do with Hyundai Tucson 2004 specifically, BEFORE they change the Clutch Master Cylinder set up.To re-iterate, the question I want to know is, does this model suffer in term of failing 1st gen clutch master cylinder and hydraulic issues?I can't find any information regarding a change in CMC. It took me 6 weeks to find a genuine part for this car. The clutch pedal feels like it's sticking going down and back up so I'm suspecting a malfunction in the design of the 1st gen early Tucson; hence why it's been changed.Thanks
Expert:  Matt replied 1 year ago.


I have no service bulletins or recalls regarding this part I'm afraid, but I have seen issues with the clutch itself breaking up so it starts to stick mechanically

Customer: replied 1 year ago.
I see. The clutch was replaced at 40 thou by previous owner and now has 90 thou on. I've only done 1 thou in it. However, the clutch itself seems fine with no slipping or judder. Just biting about 1cm off the floor, and abviously, spongy brakes.When i say 'sticking' i just mean it's not perfectly smooth going down. It was like this with before i changed the Master cylinder and the new part was sealed. I just think maybe they're defective! Why else have them changed within one year. All other CMC since 2005 have a rubber pipe coming off them. I can only assume the seal could be faulty inside. The same CMC is on the KIA Sportage, and they have been changed also.My only other assumption is a problem inside the bell housing.I'm not really sure how this site works Matt, payment wise, or how many question I can ask, but I have a couple more issues with this motor, namely a knocking or rattle from the alternator/power steering pump area. We replaced the de-coupler pulley already but it wasn't that. Next thought is the alternator or power steering bearing, but it's all money to find it out.All of my questions are really asking for common issues. I'm hoping to narrow symptoms down to typical scenaris to reduce time stripping and changing wrong parts.So, specificall, problems relating to Hyundai Tucson, and not cars in general.Thanks
Expert:  Matt replied 1 year ago.


the site takes a deposit from you at the beginning and this is held by the site until you rate my answer at which point the cash is split between the site and the expert, but you can ask as many questions on the same post as is required to resolve your issue

now if the clutch cylinder seals are breaking up then typically the fluid will be dark and sludgy as tiny bits of rubber are suspended into the fluid

regarding the spongey brakes may I suggest driving the car for a short distance and hitting the brakes hard enough to trigger the ABS and then re-bleeding the system as sometimes air can be trapped in the ABS pump which then has to be run to shift the air to the caliper

regarding the engine rattle then I'd first try removing the auxiliary drive belt and turning every pulley and ancillary ( power steering pump , alternator etc) by hand. All should turn easily (with the exception of the AC pump) with no grittyness or wobbly pulleys- If you do find a sticky pump / alternator then it should be replaced or repaired

If the engine is stone cold you can briefly run it with no belts to see if the noise changes or has gone away, this will help show if an ancillary is the issue