Wilwood Master Cyl question

[CC69Rat]

Dad and I are installing a Wilwood MC on my GMC. He has made up the lines to connect to the original front to rear lines.. etc. It's all set; however, we seem to be having a problem getting fluid from the MC to the proportioning valve. Put simply, there is zero fluid coming out of the MC at the ports where the fluid is supposed to come out. In fact, with fluid in the bowls, we disconnected the lines and no drips, no fluid, nothing.

We looked down inside the bowls where the fluid would go and we noticed this small black dial looking thing. It has an arrow on it that points to the 'front' It's about the size of a nickel. Is this supposed to stay in there? Is or could this be the cause of us not getting any fluid out if it?

1 1/8 bore, brand new booster, and the MC bench bled just fine (??) Dad said he got bubbles when he pushed the rod in. It looks normal, just no fluid just sitting there, or pressing the pedal.

What could we be missing? Is there some sort of check ball or valve we have to change and/or remove? How does fluid get from the bowl through the lines on this MC?

Does the truck need to be running before the booster will have enough pressure to push the fluid maybe?


Ideas? Thanks..

[C10_ustacould]

It's odd, the manual doesn't say anything about it.

[lolife99]

How did you get fluid when bench bleeding and not now?
(did you run hoses from the ports back into the M/C when bench bleeding?)

[CC69Rat]

The black dial things are plastic, round and just snap in / out. Underneath the mystery cap things are two small holes.. Is that how the fluid moves through the system and out to the lines?

This MC, you can also change the lines from one side to the other. Mine are on the right if you're looking at the MC mounted to the booster. Maybe it's left side from the factory and I need to move something to make it use the right side?

I paid a ton of $$ for this man, .. It shouldn't be too difficult to figure out. I think I'm just missing it. The manual / instructions dont even mention it.

[CC69Rat]

Originally Posted by lolife99

How did you get fluid when bench bleeding and not now?
(did you run hoses from the ports back into the M/C when bench bleeding?)

Dad bench bled it last week, I didn't see how he did it but he said it worked as normal. The instructions had tje hoses over in the bowls like the picture above.

Completely disconnecting the lines we should have fluid dripping out .. (??) Its bizarre
We worked on it most of the day.

[NoNeck]

Keith, I bench bled the Master Cylinder like in the photo you supplied. That's the same way I have always bench bled regular MCs. It pushed plenty of fluid through the clear bleed lines and I was able to get all the air out of it. For some reason, now that it is mounted (with a booster) there is no fluid coming from the ports.
I'm stumped...

POP

[C10_ustacould]

Hey did you use the spacer? I read in the instructions where there should be a spacer installed...

"Check the length and diameter of the push rod from the pedal or power booster. It should fully engage the bottom of the recess in the master cylinder piston assembly without interference along the sides or shoulders. For short push rod power brake boosters, use the spacer supplied to reduce the overall depth of the piston recess. The piston detail diagram on page 2 illustrates the overall depth and diameter of the push-rod recess."

[CC69Rat]

Ill call Wilwood today and see if maybe they have a tech support line (?)

Pop could it be the rod is too short or somehow came loose? Ex when you push the pedal the rod is not pushing in (like it did when it was on the bench) and pushing the fluid out?

The dinging sound when you push the pedal to the floor doesn't sound right to me.

If it takes it we can do a 7/8 bore and take the booster off.
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[NoNeck]

I think the rod length is right. I saw the spacer included in the box. I compared the length of the original pushrod "A" to the longer one supplied by Wilwood "B". They were identical in length. I even carried the master, booster and assorted pushrods to a friend of mine that operates a performance garage. He inserted the longer pushrod "B" into the booster, slipped the master on and confirmed it to be correct.

I can see if you used the short pushrod "C" that you would also need to use the spacer.

The master cylinder bench bled just fine. I'm wondering if those plastic bleed screws could have compacted the fluid holes with some plastic? There is no fluid dripping from the outlet ports with the lines disconnected. Something is not allowing fluid to exit.

Thanks for the help.

POP

[CC69Rat]

Pop .. I think we might be missing the 'Depth Correction Plug'

http://www.youtube.com/watch?feature...&v=MdkBIVgDMAU

[CC69Rat]

I have also found an older post online using HydroBoost and this Wilwood MC. They are having similar issues with it. The fix is this MC pushrod. Apparently it's longer than the one they send with the kit and is needed when running a booster.

http://www.summitracing.com/parts/wi...4/media/images

http://www.chevelles.com/forums/arch.../t-259405.html

.. read the second to last post at the bottom by 'DeeBoo'

[nlped]

I don't have that exact m/c, but I did have to use this crazy looking "bullet" adapter piece that slid inside the m/c between the internal plunger and the o.e. booster pushrod on mine. You can see the piece I'm talking about in the pic... I believe it makes up for the using of a power booster vs. manual brakes?

[nlped]

Oh, and I have the same Wilwood p/v in Pop's picture on my Fox Mustang, and it works AWESOME!!!

[shawno72]

Originally Posted by nlped

I don't have that exact m/c, but I did have to use this crazy looking "bullet" adapter piece that slid inside the m/c between the internal plunger and the o.e. booster pushrod on mine. You can see the piece I'm talking about in the pic... I believe it makes up for the using of a power booster vs. manual brakes?

That little plug makes it possible to use 2 different style boosters. Some have a long plunger and some have a shallow.

[nlped]

I knew it was something like that... I have the Cast M/C on my truck now and I had to use it with the stock p/b booster. It didn't come with the M/C originally...I had to call and fuss to CPP...

[CC69Rat]

I think that might be what Wilwood calls the Depth Correction Plug. I think the rod's too short and we just need that plug, or the push rod I posted from Summit Racing.

Pop, have you seen that plug around ? If you watched that Wilwood video it looks like it came in the plastic bag with the other plugs / fittings for the bench bleed process.

[NoNeck]

Yep, we have that plug. I just removed the master cylinder and tried it with pushrod "B" in photo.

Now the master won't even bolt to the booster. The pushrod with the plug is too long. If you use the "Depth Correction Plug" with the shorter pushrod "C" it's the exact same length as "B".

I know the master cylinder is a 1.12" Bore. I have included a photo of the model number for reference. The Depth Correction Plug is about 1.375" (see photo). The brake booster is a CPP unit.

POP

[nlped]

Get a bigger HAMMER!!!!

[CC69Rat]

Originally Posted by NoNeck

.. If you use the "Depth Correction Plug" with the shorter pushrod "C" it's the exact same length as "B".


POP

Ok, .. so can we try it with the plug? I am reading about 'the Pin doesn't seat correctly with the Wilwood MC' .. 'Once I installed the plug..' Etc.

I just have a feeling we're not putting enough pressure on the MC to push the fluid out of the ports. We know fluid will come out because you bench bled it. Why won't it come out now? It's either stopped up with something or we're simply not pushing it hard enough. I think the larger diameter of the plug doing the actual pushing and the pin pushing the plug just might give us a different result.

Worth a try.

[NoNeck]

Sounds like a good idea. I will try it later today. I am trimming hedges right now. You know about those "honey-do" lists.

[CC69Rat]

On the 'pusher' end of the original MC push rod.. is it the big end or smaller end (A in the pic) Which end is the part that goes up into the hole?

( .. Don't .. )

[knomadd]

(I'll ignore the previous statement ) Does the pedal at least feel like it's pushing into the MC? The plug might be important as I had to use one on my GTO when I did my disc conversion. It has a little indention on one end that the rod sits in to help center it on the MC piston. Apparently, if it's not centered, the piston can bind causing more problems.

You can use a piece of clay or gum or something to see if the plug is actually reaching the piston in the MC. Just be prepared to clean it out if it gets mashed in there.

If everything checks out with the plug, it sounds like your other option would be something clogging the holes. maybe the plastic pieces you were talking about before????

[CC69Rat]

It kinda makes sense that using the plug and the shorter push rod to make sure that rod is centered when it pushes the plunger down .. would be a better option than just the small end of the longer push rod.

For example, what if that push rod has kinda gotten in a bind in there? When you push the pedal down, the end of the rod has slipped and it's pushing at an angle and not depressing the plunger all the way and/or hard enough to push the fluid through the ports (?)

I'll admit, .. it's a total guess but watching that Wilwood video I feel like that plug having the coned shape in it is there for a reason. .. to keep the push rod centered up. I also feel the larger end of the original push rod (A) would essentially accomplish the same logic.

We'll see what happens. Pop I can run up after work if it helps.

[NoNeck]

Chad, I flipped the original pushrod in the photo to show how all three would insert in the master (small, rounded ends on right). It could be incapability in the CPP booster and Wilwood Master?

If you want to come by after work we can take another look at it. If your Mom knows you are coming, she will COOK dinner! If you don't, it's another cold Ham sandwich for me.

POP

[nlped]

Use the o.e. booster pushrod? I used the stock power booster pushrod (exhibit "A" in your pic), but I still had to use the little spacer doohickey to get the appropriate "push" in the M/C. Can you shoot a pic of the m/c hole where the pushrod goes? Here is a pic of my m/c...1st with the bullet spacer thingy inserted, then a pic without (the hickeybob in question is the bullet looking thing above the hole in 2nd pic).