explorer 8.8 in an a-body: experience needed

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You can go to the tires and rims section, look on page 9 the driver side is the long side, the passenger side sets equal in wheel well. Sorry that is the only pic I have posted, but like I said I will be more than glad to post for you when I get back to the states.
 
RedFish said:
The only retract action in a disc brake caliper is caused by a square ring instead of an O ring. If a rotor has enough runout to push a piston back into the caliper that rotor needs to be replaced.
There is a small amount of residual pressure in every antilock brake system. It isn't enough to heat parts, accerate lining wear, or cause any other ill effects.
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The rotor always has enough movement to push the piston further in than it should be, and this is why residual valves are made in such slight psi increments.

Who's dart here has anti lock brakes ?

Why is it when i install disc's on jeeps with antilock brake systems that also had disc drum that they also NEED a residual valve ?
Antilock brake systems aren't residual valves and they don't hold a minute amount of psi against the rear calipers.

Every car that someone adds discs to has always needed a RV and they ALL had the same problem, unless EVERYTHING was changed and done correctly from the specific master back.
 
Here's a test for you... Leave a caliper sitting off the rotor, turn the ignition switch on go to lunch. when you come back you will find the antilock system has pushed the piston out of the caliper.
I suppose I should mention my brother has been doing field failure analisis for Robert Bosch 27 years now. He knew how antilock systems operate before they went into production. That allows me to know a little more about them than I should or even want to really.
I never said a Dart has antilock brakes but I'm sure the new Dart does and the Explorer disc brakes in question did.
Unsubscibed
 
Your brother can do field analysis all week, I got a field analysis for you and your brother, and better one for you i just happen to have ANOTHER jeep here im about to do a rear disc in place of rear drum set up and add a residual valve on because it was a disc drum set up and now im making it disc disc set up and it also has antilock, how about you come over and drive it now, and then we'll put the disc's on it and drive it again and then put it on the lift and and drive it again some more and then i'll add the residual valve to factory installed ANTILOCK system already present on yet ANOTHER vehicle that has this magically making brake psi you claim your brother who does horrible field analysis doesn't understand and IF, IF the brakes work better you EAT a residual valve, IF if they do not work better with a hugely seen difference I'LL EAT a residual valve . No money, no other bets, you eat or i eat....


Im sure the explorer may have had antilock brakes, but for some odd reason i haven't read one, 1 post on any forum where anyone put the antilock brake system into there car oddly enough just the rear diff assembly without the antilock system...
 
Supershafts said:
Every car that someone adds discs to has always needed a RV and they ALL had the same problem, unless EVERYTHING was changed and done correctly from the specific master back.
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My 1993, 1st gen Explorer came with drum brakes in the rear. I upgraded the axle by adding 2nd gen disc brakes. Never changed the master cylinder, and never added a residual pressure valve. No problems what so ever....
 
OK go and drive the explorer and hit the brakes and then quickly release and hit the brakes again, and you'll see that you have a different pedal and are using 90% of the front brakes and not the rear, if you can't feel that difference in the pedal then there are other issues.

Every single person that believes they don't , have no idea they do need one, and every single person doesn't seem to notice the front brakes going out 2 ,3 ,4 times before the rear.
It is a fact you need a residual, not made up, i have shown many a customer that stuck rear discs in a vehicle that didn't have 4 whl discs what the differences are.
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Again no problems what so ever in over 100,000 miles of driving. Hitting the brakes repeatedly does not produce any strange braking effects, and the rear brakes are definitely doing their job.
 
You're telling me if you do as i told you there is no immediate difference in the pedal ??

You're either not noticing it all (which is common among the majority of operators), and or have other problems like a bad master or some special braking system that fixes itself in which you would have a ford version of Christine.

in 100k you have changed rear pads how many times ?
 
Changed the front pads twice. Still on the same rears.

The truck stops very, very, well.

I do a lot of extreme fourwheeling. There have been plenty of times that I have had to back down incredibly steep rock faces, and hills. When backing the rear brakes become the front. If there was a problem with the rear brakes it would definitely be felt in those situations... but there is no issue.
 
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I give up we're talking about a 2lb RV just enough that it keeps the pads against the rotor at all times and not backing away GIVING you the ability to have rear pads last more than 2 pad changes and 100k miles...
In 100k miles do you think that 2 front pad changes and none on the rear are the rear brakes working, think about this for a moment usually all brake bias is 60/40 on factory cars, at 60/40 how many times do you think you should change front pads and not rears if the brakes are working correctly...

Every 2nd time ? maybe even just before you need to change the fronts again for the 2nd time ?
The front brake is working or wearing 20% more than the rear... but 2 times and you think it's working right.
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Ever wonder why that happened with disc/drum, because the adjusters stop working and the front winds up doing more than 70% of the work...
So if you are changing brakes twice at the front and none at that rear.... you're beyond 75% of front brake work.
 
Any more rear brake power and the back end wants to come around. They are very well balanced for real world stopping power as is.
 
ab7fh said:
Any more rear brake power and the back end wants to come around. They are very well balanced for real world stopping power as is.
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A RV doesn't give you any more rear brake power.... A residual valve doesn't add more braking to the rear it helps to keep the piston from being able to retract, and keeps the pads just barely against the rotor so it's not taking up all the slack.... exactly like how a not adjusted properly drum brake is when the adjusters don't adjust is EXACTLY what you have all the time at the rear and the reason you have the rear pads in the back still after going thru 2 sets of front pads, when you hit the brakes you only get so much travel and so much fluid to work the pistons in the caliper, and this is why you have changed front pads twice and rear brakes 0, a normal car should be getting rear brakes just before the fronts need the second change, not 2 and keep on going, that means the rears aren't doing 40% of the work, not even 20% of the work.

A residual valve is not a prop valve, it will never make more psi at the rear, it will simply hold the pads against the rotor and take up the slack the fluid won't have to and actually put 40% of the braking on the rear, which is why your front pads are out twice and the rears are still fine.
 
Funny, but every car that I have ever done a brake job on, no matter the vintage, had the front brakes wear out sooner than the rear....

So what you are trying to say is that because I don't have a RV my pistons are retracting. Retracting means pulling away from the rotor. So you expect me to believe I am wearing out REAR brakes FASTER than I would if the pistons were allowing more brake drag through a RV???
 
You aren't listening nor understand how the system works, you do not do front brakes twice on a 60/40 designed system.

You think that when you hit the brake pedal it has enough fluid to activate the piston slack and then put the correct amount of psi on the pads per the amount of travel on the pedal, it does not, and that is why you have done brakes twice at the front and zero at the rear.

Since i have been doing brakes the rears will always go 1 past the front, (60/40 or 70/30 bias) not 2 past (95/5 bias), anytime you go beyond 1.5 times on front brakes and the rears are still in there they aren't working right or NOT ADJUSTED properly, and there is no adjustment on discs, they use different masters and valves to keep a small amount of psi on that system so the pads are always within slight contact to the rotor and there is no loss of fluid pressure to take up slack and actually apply pressure. You can only apply so much pressure with the stroke of the pedal, it doesn't magically add in additional fluid

Think of it this way, every time you hit the brakes you may move lets say a ounce of fluid...
Your wheel cylinders are not even close to the cavity of the piston in that caliper, and now when you release the pedal the psi releases and the piston moves back, that ounce of fluid isn't enough to take up the area needed to get the piston back against the rotor and then add additional pressure to work the brakes clamping force.

Now add in the minute amount of wear and now you have less force applied to work the brakes, gaining you less pad wear and less braking force, but saving you money on not having to do rear brakes.
As long as i have been working on cars and all thru my schooling NO car is set up to have 90/10 or 95/5 bias and change front pads twice and still leave the rear brakes in, that is a red flag that the rear brakes aren't working properly.

Never have i had a car that went more than 1.5 on the front whether it is a drum drum, or disc drum, or disc disc system, not even customers cars have i done front pads on twice, it usually always every other front pad change the rears are done also.
If i did do front pads on anyones cars twice there has always been a issue with the rear brakes, and either adjusters not working or AMAZINGLY someone decided you can just put discs where drums were and nothing else was needed the master was the right master for the increase fluid psi volume and valves were all perfect for the upgrade which always found out it wasn't a upgrade at all, but just the front brakes are now doing more work.
This is a huge learning experience with the 4x crowd and the jeeps that had disc drum and now have disc disc.


Im leaving you with this and im not going to continue with this.

The front uses 60%
The rear uses 40%

You have a difference of 20%

Knowing that, do you think you should have went thru 2 sets, and think you don't have a problem..
Now lets take into consideration what the new percentage is you have..

It is not 60/40, not even 70/30, most likely not even 80/20, probably like 95/5

50/50 would be if they wore out evenly, 60/40 and 70/30 is when you have to change the rears just before the fronts again for the 2nd time..
2 times and the rears are still doing nothing, thats not a 60/40 or even 70/30 split...
Start measuring the heat at the front and rear rotors, try pumping your brakes and then hitting them and see if you can even feel the difference when that happens.

Not saying you're wearing out brakes faster, but that is a fact of the problem for the front since the back isn't doing anything, but your front brakes are doing all the work and somehow you aren't seeing that as a problem..
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Not saying you're wearing out brakes faster, but that is a fact of the problem for the front since the back isn't doing anything, but your front brakes are doing all the work and somehow you aren't seeing that as a problem..
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All a RP valve would do for me is to eliminate the double pump which is necessary when the piston pulls into the caliper. Thing is I don't have to do a double pump, which means the piston isn't retracting into the caliper.

A RP has no effect on brake bias as you are claiming.
 
ab7fh, why are you bothering to argue with Supershafts? You know he always right, just ask him. :D
 
http://ecihotrodbrakes.com/brake_facts.html



Hold-Off / Metering Valves are used in the front (disc) system of a disc/drum brake system. They provide a "hold off" function to allow the rear (drum) brakes to actuate first. This function is very important in making the system function in the correct sequence in a rear wheel drive car. The rear brakes are always actuated first. This function is built into most factory type disc/drum combination valves. Make sure you have a metering/hold-off valve in the system either as a stand alone valve or as part of a factory valve.

Proportioning Valves go in the rear brake system (disc or drum) and provide for control of the rate of pressure rise to the rear brakes -- just the rate at which it builds up. Sooner or later the rear brakes see full master cylinder discharge pressure. The purpose of this rate of pressure rise control is to compensate for the reduction of weight on the rear wheels due to forward weight transfer during braking. In short, it eases the application of the rear brakes to help prevent rear wheel lockup. Factory combination valves have these built in -- make sure you know what you're getting, too little rate of rise is as bad as too much. You may not need one of these valves depending on the compatibility of your vehicle's brake system components.

Adjustable Proportioning Valves allow for fine tuning of the rate of pressure rise to the rear brakes if you have a lock up problem. If you have a lockup problem, experiment with the setting of the valve to eliminate lock up for all but all out panic stops. Good luck!

Residual Pressure Valves are used in a both front and rear brake system as follows:

2 PSI Valves - These valves are used in a disc brake system only and are required when the master cylinder is at, or below, the height of the calipers. It's purpose is to act as an anti-siphon valve preventing the brake fluid from siphoning back into the master cylinder when the brake pedal is released. Even if the master cylinder is even or slightly above the calipers, put one in anyway. If you don't and you park on a hill, fluid will siphon! These valves are cheap insurance - put them in!
NOTE: You will know if you need one of these valves if you had to pump the pedal twice to get a good pedal. See illustration for more.

10 PSI Valves - These valves are used in a drum brake system to prevent air from being ingested into the hydraulic system when you release the brake pedal. Typical wheel cylinder seals only seal when there is pressure behind them. Rapid release of the brake pedal creates a vacuum in the system which causes the seals to relax and air is ingested into the wheel cylinders. Maintaining 10 PSI in the system at all times prevents this. Some disc/drum master cylinders have 10 PSI residual pressure valves installed internally, some don't. If you're not sure, call us and we can tell you how to check. Also, some new style wheel cylinders have cup expanders which negate the need for the residual pressure valve. Either way, if you are not sure whether you have one or not, put one in. They are not cumulative and it won't hurt anything if you have two. Don't worry about brake drag, it takes roughly 75 PSI to overcome the return springs.
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Well... I am putting an 8.8 in my '65. It's $300 for a 3.73, limited slip, and rear disc brakes. I plan to buy a 2nd short axle and shortent he housing myself. I've seen 8.8s take 5-600hp with superchargers in heavy cars. I'm satisfied it's strong enough - and it looks a lot like the 7 1/4...lol. I figure with the new driveshaft and axle and misc parts I should have about $700 into it. Still less than a core 8 3/4 and all the stuff to outfit it similarly but without disc brakes.
On the disc conversion - I only have limited experience with that. but -when I ordered up the set of Baers for a customer's car, along with the hydroboost, the package came with 13" fronts, 12" rears, giant calipers, and an adjustable proportioning valve that the instrcutions had me place in the rear line. The car did have front discs originally but rear was drum and this was a competition brake package. I agree that most disc brake setups have a residual valve. However I do NOT believe it's used on the rear wheels - it's in the disc brake proportioning valve and acts on the two front wheel ports. This is why you have to get a disc brake proportioning valve when you change to front disc. I can say for certain there wasn't any recommended for the rear by Baer.
 
Put a 8.8 in my 5th ave
Came with disc brakes, plumbed em in and they work fine
The weak point on the 8.8s is where the axle tubes go into the center section, weld em up and your good
Also if you plan on driving out any distance you might wanna swap gears, the 3:55s were way to high in my 5th, at 45mph it was all R'd out
 
I am keeping mopar with mopar I picked up a 8 3/4 housing and axles from a 65-67 b-body for $75 which is roughly 3" wider than an a-body and is easy enough to make up in wheel offset I also picked up a 742 housing 3.55 clutch style power-loc for $100 so there are plenty of deals out there.
 
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