# Brake booster Replaced, front brakes now stuck partially on



## kelchm (Feb 9, 2010)

Replaced the brake booster on my mkiv gti Friday. After installation I immediately noticed that the front brakes were dragging a significant amount and that brake pedal travel feels strange -- very difficult to modulate smoothly.


Any ideas? The only thing that stood out to me was that when reinstalling the master cylinder I had to seemingly partially compress the spring in the brake booster. Is this normal? For some reason I don't remember this being the case when removing the master cylinder.


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## STVR6 (Jul 6, 2010)

Did you check and/or adjust the brake booster push rod length? Sounds like the push rod is too far out and basically kept the brakes applied at all times. It's not good for the pads, rotors, and bearings.


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## kelchm (Feb 9, 2010)

STVR6 said:


> Did you check and/or adjust the brake booster push rod length? Sounds like the push rod is too far out and basically kept the brakes applied at all times. It's not good for the pads, rotors, and bearings.


I wasn't aware it was even adjustable. Must have missed that in the Bentley. 

Turns out my ebay booster pretty much ate my master cylinder. Now ordering a new booster and master cylinder. :banghead:


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## GTijoejoe (Oct 6, 2001)

STVR6 said:


> Did you check and/or adjust the brake booster push rod length? Sounds like the push rod is too far out and basically kept the brakes applied at all times. It's not good for the pads, rotors, and bearings.


Often times the case :thumbup:
Also sometimes replacing a booster with a different one for a different car.. with a differene engine.... etc.. OR even improper adjustment of a brake pedal switch can cause drag problems.


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## STVR6 (Jul 6, 2010)

It's always good to verify the push rod lengths, even if the new master cylinder's piston is measured to be the same depth as the old one. 

You should also use a vacuum pump (Mityvac, free loaner from many parts stores, like Autozone) to pull down the vacuum because the booster compresses a little with vacuum inside. 

I would get a: http://www.harborfreight.com/6-inch-digital-caliper-47257.html






kelchm said:


> I wasn't aware it was even adjustable. Must have missed that in the Bentley.
> 
> Turns out my ebay booster pretty much ate my master cylinder. Now ordering a new booster and master cylinder. :banghead:


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## STVR6 (Jul 6, 2010)

Yeah, lucky OP's brakes didn't lock up on the highway. I hope the rotors and wheel bearings are still good. 




GTijoejoe said:


> Often times the case :thumbup:
> Also sometimes replacing a booster with a different one for a different car.. with a differene engine.... etc.. OR even improper adjustment of a brake pedal switch can cause drag problems.


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## kelchm (Feb 9, 2010)

STVR6 said:


> Yeah, lucky OP's brakes didn't lock up on the highway. I hope the rotors and wheel bearings are still good.


Oh trust me, I noticed the instant I went to back the car out of the garage.


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## STVR6 (Jul 6, 2010)

That should be fine then. :thumbup: Because it can get dangerous very quickly. 

So are you getting OEM MC and booster or off the eBay? I guess you'd probably need to get the dealer to tickle the ABS to get the air out after a MC replacement, not just a standard bleed/flush. 





kelchm said:


> Oh trust me, I noticed the instant I went to back the car out of the garage.


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## kelchm (Feb 9, 2010)

STVR6 said:


> That should be fine then. :thumbup: Because it can get dangerous very quickly.
> 
> So are you getting OEM MC and booster or off the eBay? I guess you'd probably need to get the dealer to tickle the ABS to get the air out after a MC replacement, not just a standard bleed/flush.


 Meyle master cylinder and cardone booster. I have vag-com so trigger the abs pump won't be an issue.


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## STVR6 (Jul 6, 2010)

I was thinking of getting the VAG-COM, but going through their web site they showed nothing more than turning on/off the pump. I was looking to cycle the three-state solenoids (or whatever they are). 



kelchm said:


> Meyle master cylinder and cardone booster. I have vag-com so trigger the abs pump won't be an issue.


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## kelchm (Feb 9, 2010)

So, would someone like to tell me how one goes about adjusting the push rod? I see no way to and the bently makes no mention of it. I'm thinking its non-adjustable.


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## kelchm (Feb 9, 2010)

Okay, just wanted to update this.

When I finally did tear everything down I found that the pin on the inside of the booster (which goes inside the master) had gotten cocked durring the installation. 

Lesson: make sure you put the master cylinder straight in.

Also, No, the pushrod is not adjustable.


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