Brake Master Cylinder Pushrod Issue
 

Looking at a video on YouTube, apparently there's supposed to be a crown shaped washer on the brake master cylinder Pushrod.

I suspect this washer fell into the brake booster itself upon removal. I have the Pushrod and the little metal puck thing, but can't find the washer thingy.

1. Can I replace the washer thingy easily? What's it called/part number?

2. If the old one fell into the booster (at the front of the opening there's a spring and a gap), can it stay there harmlessly or do I have to pull out the booster?

3. Is there a photo or diagram or video somewhere of how the Pushrod goes back into the booster, orientation of the little puck thing, etc?

Could you elaborate what part you are referring to.

https://c1552172.ssl.cf0.rackcdn.com/541058_x800.webp

Search YouTube for rebuild of that part. I'm sure I saw mention of a reference and it will show all the parts in order.

Attached a pic. My understanding is that it's a Booster component not a Master Cylinder component. It's what pushes against the master cylinder piston.

Honestly I don't even know what part I'm looking for. The only thing I can find on the entire internet is a YouTube video where he shows the parts but not how to put them back in.

A bunch of comments of people freaking out because there's nowhere online that explains how to put it back together.

And a response from Pelican Parts on their master cylinder DIY telling someone they probably need to replace the whole booster if the Pushrod can't go back in.

If need be I'll pull the booster and hopefully the locking ring fell into it and I can shake it out. But I still can't find anywhere that details how it fits back together.

So these parts came off on your brake booster? Never seen that happen. :dunno:

By the looks of it that retainer is what holds the pushrod in place when the master cylinder isn't there. Should be easy and obvious enough to stick that back together I would think?

That's what I figured too. First try to find that lock spring. Maybe with flexible magnet inside the booster front cavity. If you wedge the brake pedal in pressed position it's easier too see the location on the plate where the rod should be secured. That small part remains a mystery but could be obvious when you look at all the parts if it should be under the pushrod or between the rod and main cylinder.

Please post link to YouTube video you referenced.

https://youtu.be/CFK95zNMcf8


So the day I posted this, I was pissed off and went for a nap.

My wife and my dad decided to go play with the brake booster and see if they could find where that retaining ring went in order to not have me pissed off all evening lol.

My wife found it down in the bottom of the brake booster and almost had it out with a wire and hook. I took her idea and managed to hook it with the wire after putting a loop in it to use as a handle to give me some control over what direction the hook was facing. I was then able to hold my finger on it close to where we could pull it out, and she stuck a magnet on it and pulled the dang thing out! Hallelujah!

The little metal silver piece seats between the booster and the rod. Then the Pushrod goes on top of that. And then the retaining ring goes in after that.

I haven't yet done any of this. My problem is that I don't know exactly how far into the booster the retaining ring is supposed to seat?! I went to AutoZone to look at a booster but no auto parts store in the city stocks an E53 booster.

I'm about to head out to the garage to see if I can figure it out with some combination of seeing some kind of a wear mark, groove, or look at pedal travel to make sure I don't seat it too far in (although I suspect the Pushrod will just push the clip forward under pedal pressure anyway. Maybe that's how it's seating location is supposed to be determined??)

If anyone has any info on seating depth I'm all ears!

she's a keeper. If the car fell off the jack stand my wife wouldn't know that I was under the car until the weekend when she wanted to go shopping.

Haha that made us both laugh. Thanks! I agree, she's a keeper ;-) 12 years of spending almost 24/7 together and we're still best friends.

I figured out how this stupid clip goes in and I took a bunch of pics. I'll update this thread soon with a walk through on how to put it back together in case anyone else runs into this headache.

Bwahhaa

same

I can always tell something bad is about to happen...as I watch her run away to safety :rolleyes:

Brake Master Cylinder Pushrod Issue
 

Roles reversed but watch this trailer at 1:48

https://youtu.be/1ZmADkSvTF4?t=108

Update? Pics?
 

Dealing with this issue right now. Did you ever get those pics? I think the star washer is just to keep the pushrod located while master is installed/removed. Would love to see how you made out. Please let us know.

I can't find pics... But:

Make sure you don't lose the little metal round piece that goes at the base of the master cylinder. It kinda sits in the booster between the master cylinder and the booster from what I recall. Make sure it's the right way round. I believe there's an indent in your old master cylinder in the rubber that will indicate which way round it fit.

The star washer doesn't go in as far as I thought. It doesn't really snap into anything. As you said it kinda keeps the pushrod centered during installation so it lines up properly with the master cylinder on install.

The prongs face you, the rounded side of the star washer face the pushrod. I don't remember exactly how I managed to get it in, but I believe it was a combination of using a magnet to keep the pushrod out of my way, a deep tube or socket the size of the star washer, a hammer to tap it in, and possibly a screwdriver to help straighten it. The star washer bottoms out against the pushrod and the pushrod stays nice and centered in the tube.

If you drop the star washer into the booster, go make sure the brake pedal is released so you have more space between the spring coils to fish it out.

Once the overall design made sense to me the entire thing became simple and an exercise of getting the star washer to stay put on its way to being seated against the pushrod.

If I find the pics I'll post them!

PS: I used a little grease to hold the small metal disc in the booster. It goes right in the center. A little grease kept it in place while figuring out the rest. I used a telescoping magnet to set it in place and then slid the magnet down to break the magnetic connection to it.

Found some pics. I'll also DM you a link to a video I made putting the little nub thing in place.

Mine would check on me if I was working on her car but only to ask if I will be done soon or 'ask' me to do something that I know she means right now when she says when you get a chance sometime today.

I just fought this battle!

I did not realize the small part that goes in first had fallen out. We put it all back together and attempted to bleed the brakes but the pedal never felt right.
My 16 year old who is about to get a learner's permit took the first test drive. Fortunately he asked "what do I do if the brakes don't work." I told him to use the hand brake and turn off the ignition, that is exactly what he did and a good learning experience.

Realizing what a pain it was to pull and replace the master cylinder I decided this time to remove the plastic trim piece in front of it. Two nuts let me remove the AC air intake/filter housing. Then two plastic nuts and three bolts, all pretty easy to access, and the piece came it. This made is so much easier to get to the two nuts that hold on the master Cylinder as well as the two brake lines. Well worth the extra effort and eliminated a lot of dropped nuts and most of the cursing!

I put white lithium grease on the three parts that are supposed to magically stay in place when you put on the master cylinder and voila it worked. I wish I had done it this way in the first place. I would have noticed the part that was out place as you can actually see in the booster.

Good luck!
David