Brakes - Wives Tales & Misconceptions

[KULTULZ]

- 1300HP MERC COMET BRAKE FAILURE -

https://www.reddit.com/r/cars/commen...brake_failure/

[KULTULZ]

- WHILE CAROUSING WITH MY BROWSER -

To Wit - Question Asking If An External PRV Is Needed ...

You have a choice. The idea is to keep your rear shoes adjusted close to the drums. Two methods prevail, self-adjusters or residual valves.

Now we get to 'personal preference'...
When self adjusters work as they should, nothing is better because they actually turn the star wheel which expands the shoes.

Residual valves simply prevent the shoes from retracting by keeping ten psi on the hydraulic line. That means the pistons keep extending, and extending as the shoes wear. Eventually, a piston may pop right out of the bore. Yes, I've seen it happen. That leaves the rear brake circuit inoperable (with a soaking mess of brake fluid inside one drum).

11" self adjuster kits are very inexpensive and available at just about all auto parts stores. That is what I use.

Now this is on a respected FORD RELATED FORUM.

People, I am getting scared.

[rich b]

^^^
Worst part, people believe these "experts" and turn this misinformation into facts as it is repeated.

[KULTULZ]

- WHAT'S WRONG WITH THIS PICTURE -

[KULTULZ]

The below from a website discussing the GRANADA SWAP (FRT) -

When you're getting the spindle assemblies at the Salvage Yard, don't forget the distribution block. Most any post-1970 Ford distribution block for dual circuit braking systems will work.

The unit has a pressure sensing diaphragm which, when detecting a pressure drop, will close off fluid flow to the dropped circuit. This will allow you to still have either front or back brakes. Take the connector and a partial strand of the wiring, as you may wish to hook up a "Brake Warning" light later.

A diaphragm? It is a pintle (and it will not block cross-flow).

I think the writer is describing the PDV (PRESSURE DIFFERENTIAL VALVE) as FORD did not actually release a COMBINATION VALVE (an assembly consisting of two or more individual braking valves) until 1972. PDV, PPV and METERING were separate.

As for the PDV, if one does not want or need the WARNING LAMP FEATURE, actual DISTRIBUTION BLOCKS are available for a neater appearance.

While this particular tech write-up has a 2001 date, it is still online and should have been corrected (IMO of course).

[ms fowler]

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I have a friend who lives in AMC world. He constantly complains about these ne "experts" and the false information they confidently spew. I thought that maybe those people were somehow all attracted to AMC vehicles. Alas--I see they have infected FoMoCo world too.

[KULTULZ]

Originally Posted by ms fowler

I have a friend who lives in AMC world. He constantly complains about these ne "experts" and the false information they confidently spew. I thought that maybe those people were somehow all attracted to AMC vehicles. Alas--I see they have infected FoMoCo world too.

No ma'am, it is hobby wide and industry wide. I have seen some things you wouldn't believe.

[KULTULZ]

Originally Posted by KULTULZ

- 1300HP MERC COMET BRAKE FAILURE -

https://www.reddit.com/r/cars/commen...brake_failure/

Follow-up video to MERC incident -

https://www.youtube.com/watch?v=Z-FqKRHnEBE

[KULTULZ]

- BRAKE PROPORTIONING VALVES -

1. If you have the deeply-rooted need to install your own adjustable proportioning valve, be advised that they should NEVER be installed if the factory unit is still in place.

Proportioning valves in series with one another can do nasty, unpredictable things!

2. If you have the deeply-rooted need to install your own adjustable proportioning valve, be advised that they should NEVER be installed in-line to the front brakes. The effect would be to make your vehicle rear-biased before you could say “terminal over-steer.” Front brake line pressure should always be left alone – only the rear pressures should be considered for proportioning.

3. In all cases, the basic brake system balance needs to be close to optimized to start with. This is the only way that a proportioning valve can be effectively utilized. You should never assume that simply adding a proportioning valve will address all rear-bias conditions, as even the best proportioning valves must be well-matched to the target vehicle.

SOURCE - BRAKING VALVE THEORY - CENTRIC BRAKES

- https://centricparts.com/getmedia/d9...ing-valves.pdf

[Patrick brophy]

Originally Posted by KULTULZ

- WHAT'S WRONG WITH THIS PICTURE -

They have good taste in hand tools. Knipex tools are top shelve.

[KULTULZ]

You're correct there.

BUT, after scarring the hell out of the piston, won't he be surprised when the other one pops out ...

[miker98038]

I worked with a really good construction superintendent for years. The tool/caliper reminds me of his old line.

“When all you’ve got is a hammer, everything looks like a nail”

When all you’ve got is water pumps……..

[KULTULZ]

And what are the odds he didn't open the caliper bleed screws and allowed the old fluid to go back into the ABS PUMP?

[KULTULZ]

If you think that was salty, watch this procedure. He begins @ 5 seconds on the video -

https://www.youtube.com/watch?v=wSqDP-pwj2s

Now I don't know but this seems a little gnarly for me. On my personal ESCAPE, the pistons had to be rotated LH so a SPECIAL SERVICE TOOL was needed. I finally found the required adapter @ FORD of EUROPE and yes, it came from JOLLY 'OL ...

That piston is on a ratchet. You mess that ratchet up (don't even mind gnarling the piston or cutting the dust boot) and there is no self-adj feature. You then have to buy a new caliper or have in your tool box specialty tools to rebuild the caliper and also purchase service parts ($$$).

I used to see things like this on a daily basis. This is why I am so CDO (OCD in correct alphabetical order).

[KULTULZ]

Originally Posted by miker98038

I worked with a really good construction superintendent for years. The tool/caliper reminds me of his old line.

“When all you’ve got is a hammer, everything looks like a nail”

When all you’ve got is water pumps……..

It seems the BFH and HOT WRENCH are the go to instead of a specialty tool.

And if a BFH (big f*cking hammer) doesn't work, go out to the shed and find the sledge ...

(Yes, I am retaining water this evening)

[KULTULZ]

If you have the time (and have the interest), watch this video describing a COMBINATION VALVE and see if anything described is wrong (if anything is wrong) -

https://www.youtube.com/watch?v=g63mP4HwVEQ

[KULTULZ]

OK, there seems to be little interest but over 3500 hits.

Here is another discussion that should make you sit up straight -

https://57fordsforever.com/smf/index.php?topic=9149.0

[KULTULZ]

Another discussion concerning the need for a correctly adjusted MC push-rod -

https://www.jalopyjournal.com/forum/...issue.1272098/

[5851a]

I don't have more than a basic caveman education on brakes. I will only work on my own. I will not work on anyone else's brakes period. From an 81-shop manual they have a slope chart covering all the fox platform cars for the combination valve. Since all of the cars use the same brakes with exception of the wagons. Seems though they concentrated on the amount of weight of the rear of the car. Some of the cars used different size rear wheel cylinders. 1/16th diameter difference does matter. Some of the cars used a different combination valve. My 95 truck and 91 Escort wagon had a brake valve hooked to rear suspension. I assumed it was a load sensing valve to hold off brakes empty and apply more pressure when loaded. When you start messing with brakes it takes a lot of experimentation. Dual master cylinders and hydro boost are not the end all cure all. Brakes are a science; I didn't do great in science. Figured Ford's glass house had lot more smarts and time than me. Yes, there is no emergency brake, always referred it to a parking brake in manuals.

[KULTULZ]

Originally Posted by 5851a

... there is no emergency brake, always referred it to a parking brake in manuals.

BOOTLEGGER'S TURN - https://www.wikimotors.org/what-is-a...ggers-turn.htm