Parking / emergency / hand brake won't engage

[vinceparts]

So the parking brake on my 78 911sc wont work. I have replaced brake shoes, I have adjusted brake shoes just before they start dragging on the hub, and I've tried adjusting the double nut behind the hub. I pull up on the brake and get approx 8-12 clicks and its tight(hard for the mrs to let down tight) but I only get a ver very minor engagement. Park on a hill with it up and in nuetral well you may as well call the insurance company because his thing will be on a roll. Any suggestions.?

[timmy2]

Should be 3-5 clicks to go tight. Try adjusting the double nut at the rear again. You need to shorten the cable more.

[vinceparts]

Well I have no idea what's going on now. Handbrake maxed out with proper tension. Adjusters are adjusted correctly, 2 other Porsche wrenchers are confused now too. It seems like either the pins on the new shoes as well as the old shoes are in the wrong place for the cables to pull the flappy things together and spread the shoes enough or the flappy things are too short? Here's some picks so hopefully someone can help me?

As you can see the shoes only just start pulling away from the resting block?

[vinceparts]

[vinceparts]

Somebody , anybody.

[ossiblue]

Just a question.

When you replaced the shoes and you were ready to reinstall the drum/rotor, were the bow tie spreaders (one set on each side--front and back--of the shoes) fully retracted?

You might try this, adjust the brake cable so that when the brake handle is fully down, the spreaders are fully retracted. Then, shorten the cable until the spreaders just begin to move, and back off 1/4 turn. Next, install the drum/rotor and adjust the cogs until you cannot turn the wheel. Then, back off the adjuster until the wheel turns with some scraping. This should put the shoes close to the drum in the fully released position. Pulling up on the brake handle should now engage the shoes enough to stop the wheel.

[vinceparts]

Originally Posted by ossiblue

Just a question.

When you replaced the shoes and you were ready to reinstall the drum/rotor, were the bow tie spreaders (one set on each side--front and back--of the shoes) fully retracted?

You might try this, adjust the brake cable so that when the brake handle is fully down, the spreaders are fully retracted. Then, shorten the cable until the spreaders just begin to move, and back off 1/4 turn. Next, install the drum/rotor and adjust the cogs until you cannot turn the wheel. Then, back off the adjuster until the wheel turns with some scraping. This should put the shoes close to the drum in the fully released position. Pulling up on the brake handle should now engage the shoes enough to stop the wheel.

Thanks for your reply. I've tried every option. I can't get the spreaders to move the the shoes off the resting block more than 1-2mm (don't know how many inches that is). This is enough to just start dragging the brakes but no where near enough to stop it from rolling away and the handbrake handle ends up as high as it will go and the spreaders maxed out.

[ossiblue]

Originally Posted by vinceparts

Thanks for your reply. I've tried every option. I can't get the spreaders to move the the shoes off the resting block more than 1-2mm (don't know how many inches that is). This is enough to just start dragging the brakes but no where near enough to stop it from rolling away and the handbrake handle ends up as high as it will go and the spreaders maxed out.

I'm stumped. Can you post a picture of the spreaders when they are fully retracted so we can see if, in fact, they are fully retracted? From what I've been able to find, the picture you posted looks normal for the length of the spreader arms and the position of the lugs on the shoes that they press against.

BTW, are you able to lock the wheels by using the star adjusters?

[vinceparts]

Originally Posted by ossiblue

I'm stumped. Can you post a picture of the spreaders when they are fully retracted so we can see if, in fact, they are fully retracted? From what I've been able to find, the picture you posted looks normal for the length of the spreader arms and the position of the lugs on the shoes that they press against.

BTW, are you able to lock the wheels by using the star adjusters?

Yes wheels can be locked by star adjusters. Will post a fully retracted pic this arvo. My brain is telling me they should work.

I must also mention there is a big slack spot on my handbrake lever of half the height before it starts gaining tension. How do I reduce this?

[Bob Kontak]

Originally Posted by vinceparts

I must also mention there is a big slack spot on my handbrake lever of half the height before it starts gaining tension. How do I reduce this?

You got the lever. You got the cable(s). You have the mechanical brake mechanism.

Three things.

You have not mentioned (adjusting) balancing the cables at the ass end of the hand brake lever. Did you do that?

[vinceparts]

Originally Posted by Bob Kontak

You got the lever. You got the cable(s). You have the mechanical brake mechanism.

Three things.

You have not mentioned (adjusting) balancing the cables at the ass end of the hand brake lever. Did you do that?

No this is something I didn't know nor have done. Will do some searching and try it. Thanks bob

[hangar21]

Vince,
I purchased a brake CD from "yellow car garage" and followed their instructions. 3 or 4 clicks and car will not move, worked perfectly!
Good luck,
Terry

[Porboynz]

I recall there are 2 types of butterfly spreaders, maybe you have the short ones where the normal longer ones are needed. There was a thread on this years back.

[Bob Kontak]

Here is a tech article from the "Tech Info" area which you can click at the top of the forum pages.

It shows the adjustment I am speaking of (inside the cabin)

Pelican Technical Article: Parking Brake Adjustment - 911 (1965-89) - 930 Turbo (1975-89)

The article is not real clear. I think it's self explanatory once you see it though. I can help by looking at mine and then I will remember what I did. :-) Advise.

[vinceparts]

Update:
Cables adjusted so even
Slack adjusted out

Still does nothing

Pulled apart a friends sc rear brakes and found his spreaders look at more of angle than mine (see below)


So final conclusion is pins are in different locations in these shoes which requires either longer spreaders or new NEW shoes. Pain in the butt considering pelican listed these as being for my car.

[Porboynz]

Hi there Vince, in you first photo the butterfly is almost flat with both brake shoes looking like they are resting on the stops. In your post above the butterfly is at a steeper angle but one of the shoes is still off the stop. What changed there or is it the angle of the photo? I understood that the shoes should both be on the stops with the cable pulling on the butterflies just tight enough that they cannot fall out and no slack in the handbrake cables. You then fit the drum/disc and rotate the adjuster until you get binding, but can still rotate by hand, just. It pays to crank the handbrake on and off hard a few times and recheck that it is still one click off binding, then you are good to go. Worked for me.

[ossiblue]

The picture you posted of your friend's SC looks correct.

You still haven't posted a picture of your own set up in the fully retracted position. Can you do that so we can compare it with the one of your friend's?

Also, can you take measurements of the position of the pins on your friend's shoes and compare them with your new shoes?

It was never clear if your old shoes were able to keep the car stationary. Were you able to hold the car before the old shoes were too worn or did you always have issues because the shoes were worn by the time you owned the car? I think you made clear that the position of the pin on the old shoes and new replacements is the same.

This is really puzzling because I cannot find any information on different shoes for your 78, and cannot find any difference in the bow-tie type spreaders that you have.

Just for clarification, is this picture, below, of your brakes in the fully retracted position (brake handle fully down)?



I ask because I assumed it was of your brakes with the handle pulled up as far as you could get it. If, however, it's of the brakes and spreader in a fully retracted position (brake handle fully down), then the issue is the cables are too short and need to be lengthened to let the spreaders release. Then, adjust the star wheel cog.

[vinceparts]

This is the left side (same as right side) in fully retracted position.

Both sides only lift the shoes about 1mm which isn't enough for it to stop it on flat ground. When purchased the car had the same symptoms. Couldn't figure out the adjustments so assumed the shoes were worn so put these in. Threw the old ones out and same symptoms

Measurements were not taken from friends one as he wasn't keen to disassemble his completely. Only thing it can be is different length spreaders. I stumbled upon a picture of two slightly different length spreaders the other day. Was thinking adding a few mm into mine or just replace but ends up quite pricey for little pieces of metal.

[ossiblue]

Thanks for posting the picture.

Still stumped. It's hard to make accurate comparisons using the pictures because of the camera angle, but your brake pins look to be in the same place on the shoe as your friend's. Also, your spreader looks to be released to the same degree. However, the ends of your shoes do look to be closer to the center stop than those on your friend's car. As you've said, it looks like it all should work, but it doesn't.

Again, I haven't found a bow-tie type spreader that has longer wings as an OEM part, and the brake shoes all seem to be identical as well. If you could post a link to the different spreaders you stumbled upon, maybe someone can identify for which cars they are intended.

It seems there is something simple that we are missing.

[Norm01]

Are you sure the spreaders behind the shoes are properly engaged, it's very hard to see but they may be off the pin and this would cause your situation.