Brake Proportioning Valves - '02 Elantra - Comments Needed

[mcgovern61]

We picked up an '02 Hyundai Elantra about 2 years ago for my daughter to take to Florida for school (she stayed and I lost my Goldwing Restoring partner :rant: ). It had a hard time stopping in my opinion for a small car. When we first got the car, I did the usual, all brakes pads and shoes, drums and rotors cut, adjusters, tires...blah, blah, blah....

In her first two months, the car developed a ticking in the rear drums whenever she would brake. Shop looked and said drums and shoes were real dirty with brake dust...cleaned and adjusted them (only about 1,500 miles on them since I installed them?) I thought that was odd. Even after adjustment, it was still hard to stop and it wouldn't take long before it would start ticking again. I wrote it off as just the vehicle.

Fast forward.....last spring I brought the car back to NJ and no sooner was it here, I had an accident where I slid into a car in light rain. (Front brakes locked and the car kept sliding on wet leaves). Shook up, I remember thinking it odd that the rear wheels did not lock up in that kind of slide (no ABS). In short order, the front rotors warped and the front wheels have a tremendous amount of brake dust. Replaced everything again, flushed the lines and master, spring kits, new wheel cylinders, adjusted and noticed something odd while bleeding the rear for the new wheel cylinders.

While I have someone pressing the brake pedal, I can still put a little turn on the rear wheels?? (Yep they are bleed real good and adjusted tight) I started looking into the brake proportioning valves as an issue since they control the front to back braking in hard stops. The Elantra has each brake coming off the master individually (NICE!) and a proportioning valve for each rear line directly under the master.

My question is....before I decide to pull these valves (which is going to mean a complete re-bleeding at all 4 wheels) has anyone had this issue?

Thoughts??

 

[joedrum]

I bet your daughter was pissed you wreck her car.....wow that dose sound odd to be able to turn the wheel sheesh ....the porporchioning humam foot is much safer brake system ...you just explaned tech wreck ....this is high tech indangerment

 

[dan filipi]

Nope, no experience with that car but it sounds like you've done everything but the proportioning valves and the master.
I'd replace those.

 

[AApple]

For the noise....

And...

You can test the p-valves, but it requires two pressure gauges, and the adapter blocks....not something most folks have in their tool boxes.
If someone is mashing on the brake pedal, and you can turn the rear drums at ALL, they are either not adjusted properly, or there is simply not enough fluid pressure getting to them....leading you to either the master, or the p-valve....or in rare cases, a pinched line/hose. :builder:

 

[Ansimp]

I would replace the master cylinder first as proportioning valves normally don't give much trouble IMHO.

 

[mcgovern61]

Thanks Joel! Good information. That is a technical service bulletin, which is not a recall right?

The funny thing about adjusting them, they will not adjust by backing the car and pumping the brakes, but they do adjust when backing the car and pulling the parking brake (with the button depressed). That was the other thing that led me to believe the proportioning valves are not working right.

BTW, the parking brake is adjusted to 6 clicks. I can get 7 if I pull really hard, but it is only supposed to be 7 max. The light does come on even before click 1 sets

 

[Ansimp]

Gerry a lot of vehicles use the parking brake to adjust the rear shoes on a drum brakes.

 

[AApple]

mcgovern61 » Thu Jun 13, 2013 10:51 pm[/url]":1bnp8jme]That is a technical service bulletin, which is not a recall right?

Kerrect. Just something I found that had to do with a noise.
Another thing too...if the rear drums have been machined, it's possible they have been cut too much, and are now so over sized the shoes just won't grab as they should. A lot of these newer cars(newer than 1990's era) have drums/rotors that are thin(er) to begin with, to save weight. Sometimes they are not even meant to be machined...just replaced. :builder:

 

[mcgovern61]

AApple » Fri Jun 14, 2013 6:28 am[/url]":2vbvux0b]

mcgovern61 » Thu Jun 13, 2013 10:51 pm[/url]":2vbvux0b]That is a technical service bulletin, which is not a recall right?

Kerrect. Just something I found that had to do with a noise.
Another thing too...if the rear drums have been machined, it's possible they have been cut too much, and are now so over sized the shoes just won't grab as they should. A lot of these newer cars(newer than 1990's era) have drums/rotors that are thin(er) to begin with, to save weight. Sometimes they are not even meant to be machined...just replaced. :builder:

Thought of that last spring and I did replace the rotors and drums then.

 

[OldWrench]

Your comment about excessive brake dust leads me to wonder what kind of brake shoes and pads you are buying. Are you using OEM shoes and pads or aftermarket? It is obvious you have a problem with either the master cylinder or the p..valve. One other thing I have seen is the flexible brake line will deteriorate internally and cause restricted flow, but normally that is just to one wheel.

 

[mcgovern61]

OldWrench » Fri Jun 14, 2013 9:12 am[/url]":3kj1h0b4]Your comment about excessive brake dust leads me to wonder what kind of brake shoes and pads you are buying. Are you using OEM shoes and pads or aftermarket? It is obvious you have a problem with either the master cylinder or the p..valve. One other thing I have seen is the flexible brake line will deteriorate internally and cause restricted flow, but normally that is just to one wheel.

Again, good points. When I replaced the pads and shoes, I purchased OEM from Hyundai hoping that it would make a difference. Of course, they assured me that using non-OEM or aftermarket pads and shoes surely was the problem! :doh: :hihihi:

 

[OldWrench]

There are some very good aftermarket pads and shoes available, many of the less expensive ones will wear fast and also create a lot of brake dust. I have good luck with NAPA quality pads.

 

[slabghost]

Brakes wear a lot more quickly if the drivers "ride" the brakes. Many around here do as evidenced by the brake lights. I never liked any of the brake antilock junk.

 

[dan filipi]

OldWrench » Fri Jun 14, 2013 1:31 pm[/url]":1m9qx6pu]There are some very good aftermarket pads and shoes available, many of the less expensive ones will wear fast and also create a lot of brake dust. I have good luck with NAPA quality pads.

I replaced rotors, pads and rear brakes, and turned the drums on a Ford van I had.
The rotors grooved and ground down in 500 miles.
Never did figure out why that happened.
Shortly after I scrapped the van. It was a piece o crap in many other ways.
Just sayin I think there can be pad/metal combinations that might not play nice together.

 

[Ansimp]

Another reason to be confident that the master cylinder is doing its job properly. As many on this site are aware with the GWs it doesn't take long to ruin brake pads and rotors if they don't release correctly.

 

[OldWrench]

The rotors grooved and ground down in 500 miles.

Normally there are only two things that will cause that. If it happened to both front brakes then I would suspect the master cylinder either faulty or miss adjusted. If the plunger in the master cylinder doesn't return all the way it will not allow the fluid to return causing the brakes to drag. The only other issue would be calibers but I can't imagine both sticking at the same time.

 

[scdmarx]

What, no pictures?

 

[mcgovern61]

I shall have to work on pics!