Brake Question - Bleed MC?

BrightVa · Aug 8, 2023

1995 GT - In process of upgrading the front brakes to Cobra style, replacing the rear calipers/rotors/pads, and installing braided steel hoses on all 4 calipers plus the one over the rear differential.

After removing the front calipers and replacing the front hoses, I happened to glance at the master cylinder and noticed the reservoir was totally empty. I have NOT touched the brake pedal, so it just gravity drained when the hoses were removed.

The question: Do I need to remove the master cylinder and bench bleed it?

Thanks for any advice you have!

limp · Aug 8, 2023

Are all of your lines hooked up? I would try to gravity bleed it first and see what happens..

BrightVa · Aug 8, 2023

Yes, the lines are all hooked up on the master cylinder and ABS, I haven't touched them. I just removed the hoses from the calipers, then the hoses themselves.

Mustang5L5 · Aug 8, 2023

If air finds its way into the MC bore, it usually traps in the front tip of the MC and is hard to bleed out unless you bench bleed. Really all you can do is top off the MC and bleed the brakes and try it.

With engine off, pump the pedal (after you top off and bleed) and if it's hard as a rock you are good. If it's spongy at all, you'll likely need to bench bleed. You can sometimes cheat and do it by jacking up the rear of the car VERY high so that the MC is level. However i find doing it off car is easier as you'll want the MC level and the ports slightly up.

AeroCoupe · Aug 8, 2023

I’m going to caution you to not pump the pedal with air in the lines with an ABS module in the car. You can lock the piston up in it. The best way to bleed them is with a power bleeder but gravity will also work.

Watched a guy try and manually bleed an ABS car in the paddock at Hallett and ruined his weekend when the ABS unit locked up.

I have ABS from a 95 car in my Coupe so I use a Motive Bleeder on it every time.

Anyhow, just an FYI so proceed as you see fit.

BrightVa · Aug 9, 2023

Thanks so much for the replies. I've never removed/replaced a master cylinder, but it doesn't look like a very hard job. So I'll plan to remove and bench bleed it just to be sure and in the interest of not having to bleed the lines twice.

I don't have a power bleeder, but I do have a vacuum bleeder. I'll use low pressure and patience until the lines are flowing good.

BrightVa · Aug 9, 2023

Separate question, but related to this brake job: So last night I replaced the rear brake hoses.

In order to remove the old ones, I had to unbolt the bottom of the rear shocks.
To my surprise, neither of the shocks extended after being unbolted. In fact, the driver's side shock actually retracted about a half an inch up (towards the top of the car).
Now I can't get the bolt back in. I lay on the ground pulling down on the shock as hard as I could and it wouldn't extend a bit.
This is with the rear axle on jack stands (not the frame, but the axle), so the rear suspension should be in a partially compressed state. Meaning those shocks should have extended a bit once the bolt was removed. Or at least that's how it seems it should be.

Question: does this mean those shocks are done and I should go ahead and replace them both?

Pic attached.

Mustang5L5 · Aug 9, 2023

Those look like original ford shocks. At 30+ years old, I’d replace those.

But yes, the behavior doesn’t suggest they are in good condition anymore

BrightVa · Aug 9, 2023

Mustang5L5 said:
Those look like original ford shocks. At 30+ years old, I’d replace those.

But yes, the behavior doesn’t suggest they are in good condition anymore

That's what I figured. Just thought I would check.

I'll go ahead and buy a full kit and replace the quad shocks and the fronts too. Any suggestions on shocks? I see LMR has several options at several price points.

This will be a street car only, and remain at stock ride height. There is certainly some "spirited" driving in its future, but nothing too crazy. So I don't want anything overly stiff.

limp · Aug 9, 2023

BrightVa said:
That's what I figured. Just thought I would check.

I'll go ahead and buy a full kit and replace the quad shocks and the fronts too. Any suggestions on shocks?

Monroe or Gabriel gas shocks.....

AeroCoupe · Aug 9, 2023

If you plan on putting good lower control arms on the rear end at some point with new stock upper control arms just put the stock quad shocks back on and save the money. With quality LCA's and new UCA's the quad shocks are pointless.

90sickfox · Aug 9, 2023

You can bleed the master cylinder without removing it. A helper will be needed to do it though. Have them slowly push the brake pedal. When they start pressing crack loose the line closest to the brake booster. It will squirt fluid out so have a rag handy. When the pedal is all the way down tighten the line. Now, slowly let the brake pedal back up. You'll need to do this 3 or 4 times starting at the end colsest to booster and ending with the line at the front of the master cylinder. After doing that you can move to the right rear amd bleed as normal. Pump them up....hold it down...crack bleeder...tighten bleeder.

I like using a Mightyvac vacuum pump to bleed brakes now. Keeps me from needing someone to pump the brakes.

FYI....brake fluid is hygroscopic meaning water completely absorbs it to a molecular level. If you spill any use water to emmediatly rinse off wherever it spilled. I had an instructor that would but brake fluid in a cup of water and drink it. I don't advise it.

BrightVa · Aug 10, 2023

limp said:
Monroe or Gabriel gas shocks.....

Thanks. Neither of those get much love on the various mustang forums. I'm guessing that's because those people are running lowering springs and these shocks are not designed for that application? I don't mind spending the money for good quality, but if the Gabriel's are good, I'll gladly save several hundred dollars.

85GTStangGuy · Aug 10, 2023

AeroCoupe said:
If you plan on putting good lower control arms on the rear end at some point with new stock upper control arms just put the stock quad shocks back on and save the money. With quality LCA's and new UCA's the quad shocks are pointless.

Or just leave them off....

limp · Aug 10, 2023

BrightVa said:
Thanks. Neither of those get much love on the various mustang forums. I'm guessing that's because those people are running lowering springs and these shocks are not designed for that application? I don't mind spending the money for good quality, but if the Gabriel's are good, I'll gladly save several hundred dollars.

For what you are doing with your car, these shocks are more than adequate... Just don't use KYB's...
If you want to spend a $1000 on Koni shocks I am sure they will help your car handle a little better..

BrightVa · Aug 10, 2023

limp said:
For what you are doing with your car, these shocks are more than adequate... Just don't use KYB's...
If you want to spend a $1000 on Koni shocks I am sure they will help your car handle a little better..

Great, thanks so much! I went ahead and ordered the Gabriel kit from LMR. $234 with free shipping. I thought that was a pretty good deal. It includes the fronts, rears, and the quads.

Yea, being a convertible, I see this car as a cruiser (hopefully with better power and better brakes by the time I'm done working on it). The ride quality is more important than handling curves.

G G · Nov 9, 2024

BrightVa said:
Separate question, but related to this brake job: So last night I replaced the rear brake hoses.

In order to remove the old ones, I had to unbolt the bottom of the rear shocks.

To my surprise, neither of the shocks extended after being unbolted. In fact, the driver's side shock actually retracted about a half an inch up (towards the top of the car).

Now I can't get the bolt back in. I lay on the ground pulling down on the shock as hard as I could and it wouldn't extend a bit.

This is with the rear axle on jack stands (not the frame, but the axle), so the rear suspension should be in a partially compressed state. Meaning those shocks should have extended a bit once the bolt was removed. Or at least that's how it seems it should be.

Question: does this mean those shocks are done and I should go ahead and replace them both?

Pic attached.

Assuming these are gas charged shocks, yes, when completely freed from the chassis at the bottom, the shock should extend to its fullest length. If they are only hydraulic shocks (not gas charged) then, no, that could be normal.
You could always reconnect them and see how it rides or look for tire wear. If the shocks are shot you will get feathering on the tires (high and low treads mainly on the outer edge of each tire). If you see that, replace the shocks.

Gary

BrightVa · Nov 9, 2024

G G said:
Assuming these are gas charged shocks, yes, when completely freed from the chassis at the bottom, the shock should extend to its fullest length. If they are only hydraulic shocks (not gas charged) then, no, that could be normal.
You could always reconnect them and see how it rides or look for tire wear. If the shocks are shot you will get feathering on the tires (high and low treads mainly on the outer edge of each tire). If you see that, replace the shocks.

Gary

Thanks for the reply! I actually replaced them a few months ago.

Brake Question - Bleed MC?

BrightVa

Member

limp

wrap a little cheese around it and its a done

BrightVa

Member

Mustang5L5

That is…until I whipped out my Bissell

AeroCoupe

lube between the nut and the face. I know my lubes

BrightVa

Member

BrightVa

Member

Mustang5L5

That is…until I whipped out my Bissell

BrightVa

Member

limp

wrap a little cheese around it and its a done

AeroCoupe

lube between the nut and the face. I know my lubes

90sickfox

Wasn't a pretty sight...and I've got big hands

BrightVa

Member

85GTStangGuy

limp

wrap a little cheese around it and its a done

BrightVa

Member

G G

Member

BrightVa

Member

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Brake Question - Bleed MC?

Member

wrap a little cheese around it and its a done

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That is…until I whipped out my Bissell

lube between the nut and the face. I know my lubes

Member

Member

That is…until I whipped out my Bissell

Member

wrap a little cheese around it and its a done

lube between the nut and the face. I know my lubes

Wasn't a pretty sight...and I've got big hands

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wrap a little cheese around it and its a done

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