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Brake Master Cylinder Related Question

Posted By: SPWC

Brake Master Cylinder Related Question - 12/24/08 09:14 PM

I just got my Reman'd Brake Master Cylinder(Its not a Cardone Unit) I noticed that in the plastic bag that the Master cylinder is in,theres this little rubber piece. What is it?What does it do,is it absolutely necessary?

IIRC it goes in the bore where the pushrod goes into(it appears to fit perfectly)but I cant remember 100%.

Do I put it in the hole or does it go in the pushrod itself,having it rest in the little groove right after the tip of the pushrod?

Any help would be great since installation of the master and bleeding of the 4 wheels is all thats keeping this car from its first drive under its own power since 1995.

Attached picture 4899434-003.jpg
Posted By: 70Duster

Re: Brake Master Cylinder Related Question - 12/24/08 09:27 PM

Pop it onto the pushrod, then push the pushrod into the M/C. A little light lubricant will help it slip together easily. And, yes, it is necessary since it will prevent the pushrod from coming out of the M/C if someone pulls the brake pedal back far enough.
Posted By: Lefty

Re: Brake Master Cylinder Related Question - 12/24/08 09:30 PM

That little piece prevents your MC pushrod from falling out and you from having a very, very bad day.
Posted By: SPWC

Re: Brake Master Cylinder Related Question - 12/24/08 10:13 PM

Well looks like I may have jumped the gun. I went ahead and put the piece into the master cylinder,and then installed the master. I bench bled the master while on the car and then reinstalled the lines on the master.

I pulled out all the bleeder screws,cleaned and reinstalled,and then applied pressure to the pedal,thinking that me pushing on the pedal (pushrod) would push it into the rubber piece. I hope im right!!

Now im waiting for my stepson to get out of the shower to help me bleed the brakes.
Posted By: RapidRobert

Re: Brake Master Cylinder Related Question - 12/25/08 12:45 AM

Is this MC a manual brake unit that has the machined recess for this piece to fit into. You'll have to take it out of the MC & slip it on the pushrod
Posted By: sthemi

Re: Brake Master Cylinder Related Question - 12/25/08 01:19 AM

Do not use the rubber ring on a POWER Brake car, only Manual Brakes get the ring.
I think I used a few drops of brake fluid to lube mine, it was still hard to push in all the way.
Posted By: SPWC

Re: Brake Master Cylinder Related Question - 12/25/08 02:43 AM

Quote:

Is this MC a manual brake unit that has the machined recess for this piece to fit into. You'll have to take it out of the MC & slip it on the pushrod



Yes it is a Manual Drum brake system on this car. Looks like im gonna hcve to undo everything again,luckily,its not that difficult. Wondering if I can do the roval without disconnecting the lines at the master,anyone ever try,without kinking the brake lines?

*EDIT*

I went ahead and unbolted the Master Cylinder and tried pulling it from the firewall,It wouldnt budge,so then I unhooked the brake lines going into the master and it came out a little,and wouldnt go anyfurther,whereas before with the old non functional MC the darn thing about fell off the firewall once I unbolted it and removed the lines.There was no rubber grommet on the old MC

Would anyone care to speculate,that my Pushrod is seated firmly(correctly) in the rubber groommet according to the description ive given above?
Posted By: Chris2581

Re: Brake Master Cylinder Related Question - 12/25/08 04:04 AM

Pull the master cylinder and make sure it's on the pushrod.
Posted By: belv2vert66

Re: Brake Master Cylinder Related Question - 12/25/08 02:55 PM

Quote:

Quote:

Is this MC a manual brake unit that has the machined recess for this piece to fit into. You'll have to take it out of the MC & slip it on the pushrod



Yes it is a Manual Drum brake system on this car. Looks like im gonna hcve to undo everything again,luckily,its not that difficult. Wondering if I can do the roval without disconnecting the lines at the master,anyone ever try,without kinking the brake lines?

*EDIT*

I went ahead and unbolted the Master Cylinder and tried pulling it from the firewall,It wouldnt budge,so then I unhooked the brake lines going into the master and it came out a little,and wouldnt go anyfurther,whereas before with the old non functional MC the darn thing about fell off the firewall once I unbolted it and removed the lines.There was no rubber grommet on the old MC

Would anyone care to speculate,that my Pushrod is seated firmly(correctly) in the rubber groommet according to the description ive given above?



I would guess it is seated. One method of removing the rod is done basically just as you described. Loosen the master bolts as far as you can, place a spacer between it and the firewall and then go in and pull back on the brake pedal. Ironically, I just installed mine yesterday also, I spit on the grommet, installed it in the recess in the master, and then put the rod in. I did it on the bench tho. I considered putting the grommet on the rod first but I thought the sharp edges around the master recess and the edges of the grommet would be a bad combination.
Posted By: jbc426

Re: Brake Master Cylinder Related Question - 12/25/08 03:02 PM

If you can't pull the rod out of the master cylinder, the little rubber grommet is doing it's job.... Depending on how your brakes are adjusted etc, the rod would/could slide right out leaving you with no brakes if someone pulled the brake pedal up if the rubber wasn't in there at all, hence the reason the engineers put it there. I put the grommet in the M/C making sure it was lined up properly and then assembled the rest. it snapped together when I pushed the brake pedal. It wouldn't pull out easily later when I had to remove the rod and M/C.
Posted By: RapidRobert

Re: Brake Master Cylinder Related Question - 12/25/08 04:33 PM

Sounds like it did get seated the 1st time & my advice was in error. I had several where the pushrod would not slip inside the grommett when it was put in 1st,it just ended up jamming the grommet to the rear. Shove it back in there & if it locks you're good or if it's damaged a piece of vac line will work good. I apologise for the erroneous advice & the added work I caused you.
Posted By: SPWC

Re: Brake Master Cylinder Related Question - 12/25/08 06:02 PM

Quote:

Sounds like it did get seated the 1st time & my advice was in error. I had several where the pushrod would not slip inside the grommett when it was put in 1st,it just ended up jamming the grommet to the rear. Shove it back in there & if it locks you're good or if it's damaged a piece of vac line will work good. I apologise for the erroneous advice & the added work I caused you.




No worries,better safe than sorry,seriously dont sweat it,we are all on a different level of experience.Heck I didnt even know what the piece was and thought of throwing it away.
Posted By: sthemi

Re: Brake Master Cylinder Related Question - 12/26/08 07:20 AM

On a releated note, did you put the dust boot retainer on the new master in place of the stamped finger used on power brake cars?
Posted By: farmington

Re: Brake Master Cylinder Related Question - 12/26/08 11:17 AM

I've always put the rubber in the M/C, mounted the M/C, gave the pushrod a shot of wd-40 and pushed on the brake pedal. It's always gone right in.
Posted By: SPWC

Re: Brake Master Cylinder Related Question - 12/26/08 03:41 PM

Quote:


On a releated note, did you put the dust boot retainer on the new master in place of the stamped finger used on power brake cars?



There is/was nothing that resembles what you are talking about on the old or the new MC.
Posted By: RapidRobert

Re: Brake Master Cylinder Related Question - 12/26/08 04:49 PM

Quote:

the stamped finger

I saw a MC with one of those but I dont remember what the app was.
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