Need outside opinion…. Brake Booster 03 Santa Fe

[Ryan]

Hello All! Glad to be here among good people! I’ve learned a lot of invaluable information from Eric, and looking forward to sharing any experiences I’ve had in the last 20 years of wrenching my own vehicles to hopefully help “Fix it forward”!

I’m just seeking an outside opinion on a job I’m currently working on, while I’m waiting for the part in the morning.
I’ll try to be as detailed and as brief as possible.
Here goes,

Vehicle being serviced:
2003 Hyundai Santa Fe 2.7l V6

A Brief History:

Customer complains of hard brakes.
Customer takes vehicle to dealer for a quote of $1500
Customer says F*@K THAT then asks me
I tell him to order the part #. I’ll fix it.
I replace said part and compress the calipers to force the air out of the master cylinder instead of pushing air the other way through the system.
Grease Contact points at all 4 wheels.
Replace Wheels, test drive, A-Ok!
Customer leaves. Calls Back 20min later, Front Passenger wheel locked up and started smoking…… WTF!?
After taking all the wheels off again and re-checking everything…… compress caliper. Pad comes right out. Nothing abnormal WTF!!?
I put it back together…… AGAIN.
Back to normal brakes fine.
2nd test drive…. After 20min driving, I stop the vehicle to go into store. When I come out and try to back out…. caliper locks up again. WTF!!!!!!?????
Wait a half an hour start it up. BACK TO NORMAL AGAIN!
Thoroughly agitated, I ask look up the part # and sure enough. He ordered the booster for the 3.5l engine instead of the 2.7 like he needed in the first
place. He was under the impression he had the 3.5……… Sheesh….

MY QUESTION FINALLY IS……….. When I put the CORRECT part in, will this fix the problem, or is it further down the line and should also be looking somewhere else?
Any and all questions & opinions are welcome including:
WHY THE EF WOULD YOU LET THE CUSTOMER ORDER THEIR OWN PART? He’s a friend for 20 years and I should have known better.

Yet another lesson learned.
Hope that wasn’t to long winded….
Thanks in Advance Good People!

Topic

[dan]

what condition are the break hoses?

Sometimes what happens is a peace of rubber breaks off on the inside and acts like a one way valve on break hoses, i have seen it myself personally, what happens is the person presses the brakes and it feels normal for the first few times, but eventually the peace of rubber acting like a one way valve traps enough pressure in it keeps the breaks partially applied, then as the vehicle sits long enough the pressure has enough time to escape.

a good way to test this is pump the breaks a lot! then see if that caliper locks up, if it does as fast as you can before the pressure can escape open the bleeder screw on that caliper, if fluid squirts out under pressure that is a good indicator a hose needs replaced because a peace of rubber inside is acting like a one way valve not letting pressure back when the pedal is released.

If the break hoses are in really bad condition may try replacing those…can’t see how a break booster would cause one single caliper on the entire break system to lock up to the point the pads start to smoke.

could be a caliper issue itself too, sometimes caliper start to stick… but do some diagnosis before replacing parts.

[Ryan]

Great Insight 13ace!

I’m going to replace it with the correct part to start to rule that out first. Especially since I already removed it! lol!

However, Your suggestion is the first thing I’m going to look for when it is the correct part.

I would have pulled my hair out diagnosing further the same issue with dwindling culprits.

The hose looks OK on the exterior, but that doesn’t mean it is inside.

I do think, good Sir, that you may have saved me a lot of time and aggravation going forward.

Thanks Given, and Karma up to you Bro!

Hope I can help you out in the future!

Thanks also for the speedy response!

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• plateauLee.jpg

[dan]

you’re welcome.

I am not saying a bad break hose will be your issue, but just in case, pump the breaks up a lot, if that caliper locks open the bleeder screw see if some fluid streams out like its under pressure.

[Ryan]

OOOOOOOOOKAAAAAY…….. So,

When I took everything apart again, It appeared to not let as much fluid out the second time. and air bubbles were released when wrenching 1 fitting. Leading me to believe the fluid never moved? Wouldn’t the brakes be spongy? they felt fine til they locked up after heating. Also, Is the unit underneath the MC a proportioning valve? Or, ABS Unit? I’m a bit confused. I’ve been reading the same terms forever now…… :blink:

2nd attempt…..
Put CORRECT booster in.
back bled brakes to keep air from going through whole system.

Worked great for about an hour the…. Same problem at same wheel.

Here’s my guess as to what’s happening…..
while researching the hyundai forum, I discovered that the bleed pattern is not the most common that I believed it was, and that is the procedure I went with. Which was :

RR
LR
RF
LF

Apparently, the bleed pattern should be:

RR
LF
LR
RF

Could this be the culprit?
Customer now also complains of a hard pedal just as if the part was never replaced. I still have yet to drive it however so that, I cannot confirm

I think it’s also pertinent to note that when I back bled, (in the wrong order) I Didn’t get any rise in fluid in the MC until the last wheel. I figured I should get less by the last wheel. I guess that would come back to the bleed pattern.

I also can’t seem to get an answer on weather a hi-scan (pro)tool should be used. AutoZone’s website seems to think so.

At any rate, he’s dropping it off tomorrow, and I was planning on giving the “correct” bleed order a go. With or without the scan tool.

Anyone have a preferred bleed method?

I hope I’m not leaving any important details out.
I need to get this car out of my hair already!

To top it off…… This morning, my heater core hose hard fitting broke off at it’s motor connection on my pickup

………………. But Thaaaaaaat’s a story for another thread folks…. COMING SOON!

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[EricTheCarGuy]

OK first, you don’t often need to bleed the brakes when replacing a booster. Just unmount the master cylinder and move it forward with the brake lines still connected. This will save you a BUNCH of time and effort.

By the sound of it, the pushrod in the booster may not be adjusted correctly. I don’t know the service procedure for that model, but the length of that rod needs to be correct or it can cause the very issue you’re having.

To test my theory, try loosening the master from the brake booster to see if the wheel still hangs up. If it doesn’t, then the pushrod is adjusted too tight and needs to be backed off a bit.

More info on solving brake problems here.

http://www.ericthecarguy.com/faq/solving-brake-problems

Please keep us updated on your progress.

[Ryan]

[quote=”EricTheCarGuy” post=149531]OK first, you don’t often need to bleed the brakes when replacing a booster. Just unmount the master cylinder and move it forward with the brake lines still connected. This will save you a BUNCH of time and effort.

By the sound of it, the pushrod in the booster may not be adjusted correctly. I don’t know the service procedure for that model, but the length of that rod needs to be correct or it can cause the very issue you’re having.

To test my theory, try loosening the master from the brake booster to see if the wheel still hangs up. If it doesn’t, then the pushrod is adjusted too tight and needs to be backed off a bit.

More info on solving brake problems here.

http://www.ericthecarguy.com/faq/solving-brake-problems

Please keep us updated on your progress.[/quote]

Thanks a ton Eric!

Unfortunately, I wasn’t so lucky as to just be able to remove the MC and pull it back to remove the booster. The way the lines were bent made it impossible. I DID however have to loosen the bracket that holds…… proportioning valve is it?……. To pull it even further forward without having to remove any more lines. The ones going out to the wheels were not touched at all.

Anyway, here’s the latest……

Loosened the MC a bit (the nuts did seem a little tight) and messed with the adjustment rod a bit and sent him on his way. 15 min later he pulls back in with the brakes locked and the brakes rock hard ……. WTF!!!!!!! :angry:

In a fit I crawl under the dash with it still running and loosen the CRAP out of the push rod. All of a sudden the brakes release as I’m doing it.

Coincidence? I hope not.

Sent him on his way for the 50th time it seems but have not heard back since…. Guess I’m not bleeding em?

Either it fixed the problem, or he got fed up and took it to someone else…..

All I know is it’s been out of my driveway for the longest time in like 5 days.

Thanks again everyone for all your help! Now I have to deal with my heater core hose broken off. See you in the next post…. :unsure:

[Author]

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