kishy's 1985 Ranger

[kishy]

I looked it up and rather annoyingly, the bonded brake shoes that failed were Wagners...so I can't really trash talk them too much. Riveted Wagner is what I put on to replace them.

I can only assume the combination of being bonded, and perhaps old stock, resulted in the adhesive failing and the linings falling off. When replacing them yesterday, the ones on the other side popped off with almost no effort required as well. My idiot self had assumed the shoes would not be able to travel far enough, even minus their linings, to let the piston pop out of the WC. Lesson learned, there is more than enough room for that to happen.

Master is next (this coming weekend). I think there's an internal seal failure preventing the front brakes from pressurizing. With the rear fluid loss and safety valve activation, I should have had full front brakes, but I had almost nothing at all. The fronts bleed normally, but can't stop the truck on their own and that's a problem. The odd thing is that the rear shoes had tons of material left so if the truck was 100, or even 75% stopping on the rears I would have expected more wear.

[85crownHPP]

Nice! It reminds me of my '89 BII, I miss that thing. Someone insisted on giving me $2k for it, so I let it go...

[DerekTheGreat]

I could write a book on how the process goes wrong from concept to finished product.

Give me the Cliff Notes version, please

But also, say a problem is found in the field with a given design, how do they find the problem, is it via customer complaint or do they continue to test the products and designs after they're released?

[gadget73]

Old bonded adhesive becomes un-bonded adhesive. Thats the usual fail method on 90s+ Panther parking brakes. The friction material simply falls off the shoe.

[sly]

I could write a book on how the process goes wrong from concept to finished product.

You should do that.

[turbo2256b]

I spray the under side of my vehicles with Chain saw bar lube lasts for years works better than under coating.

[DerekTheGreat]

Coatings are shit, trap moisture. Oil/lubes are certainly better, just be mindful of the chemistry and what not around rubbers & plastics.

[BigMerc96]

Give me the Cliff Notes version, please

But also, say a problem is found in the field with a given design, how do they find the problem, is it via customer complaint or do they continue to test the products and designs after they're released?

Heh. I knew a guy who was a powertrain failure analyst for Chrysler back in the day. Basically he'd take a engine/trans design prototype and run it on a dyno till it broke then figure out how it broke and recommend changes. I remember clearly that he found early 3.5l DOHC V6s would pop head gaskets, which was a problem that continued on production engines. Why? When he reported the issue, he was told that it was too far along in the engineering/design phase to fix it. At some point they did, but it wasn't until several years into production. I imagine that is a fairly common scenario. Something doesn't get discovered/realized early on and by time it is the design is too far along or there isn't enough time to change/fix it unless its something simple.

[turbo2256b]

I had a work order that had to do with a thermostat hsg. It was on one of fords 4 bangers. It was a very complicated hsg design with a lot of stack up / tolerance issues. Had to read through about 2000 reports written by dealership mechanic sorry service technicians. Some really didnt explain the issue some did. Some were because of sand that wasnt flushed out well after the casting of the block. Some the malfunction of the thermostat. Most because of the hsg itself. So I ADJUSTED some of the pieces making up the thermostat assembly to correct. Funny part was I told the engineer how it should have been done a much cheaper and wouldt have any issues. He said were were you when this was designed? I told him i was sitting right next to the guy designing the oil pan for the stroked 2.3. aNY WAY IT was to late to change to my better design as the engine already in production.

[DerekTheGreat]

Heh. I knew a guy who was a powertrain failure analyst for Chrysler back in the day. Basically he'd take a engine/trans design prototype and run it on a dyno till it broke then figure out how it broke and recommend changes. I remember clearly that he found early 3.5l DOHC V6s would pop head gaskets, which was a problem that continued on production engines. Why? When he reported the issue, he was told that it was too far along in the engineering/design phase to fix it. At some point they did, but it wasn't until several years into production. I imagine that is a fairly common scenario. Something doesn't get discovered/realized early on and by time it is the design is too far along or there isn't enough time to change/fix it unless its something simple.

Very interesting! Stupid move on management's part. Guess that goes back to failure analysis and damage assessment. Like what costs more, pull the engine or deal with warranty concerns? Still, that's a shitty thing to make your customers deal with it, not good for reputation. I hate management, damn bean counting, pencil pushing morons with no concern for the consequences of their actions.

[DerekTheGreat]

I had a work order that had to do with a thermostat hsg. It was on one of fords 4 bangers. It was a very complicated hsg design with a lot of stack up / tolerance issues. Had to read through about 2000 reports written by dealership mechanic sorry service technicians. Some really didnt explain the issue some did. Some were because of sand that wasnt flushed out well after the casting of the block. Some the malfunction of the thermostat. Most because of the hsg itself. So I ADJUSTED some of the pieces making up the thermostat assembly to correct. Funny part was I told the engineer how it should have been done a much cheaper and wouldt have any issues. He said were were you when this was designed? I told him i was sitting right next to the guy designing the oil pan for the stroked 2.3. aNY WAY IT was to late to change to my better design as the engine already in production.

So did the eventually phase your fix in or just let it go? Why don't they catch that stuff before production hits? Don't the test engines for several years before production?

[turbo2256b]

They fazed in my fix of the original design but didnt go with my better , cheaper, simpler design. Would have if the original wasn't already in production.

[kishy]

Pics of the brake carnage from Tuesday:





Today, replaced the master cylinder out of "an abundance of caution":



That adjustable pushrod the people talk about:







The old MC had been actively leaking against the booster, so this was needed. The brakes feel pretty much the same after bleeding, but now it will lock up the fronts if I really try, so it's better all around.

I took it to the shop that did the safety on it 2 years ago and had the technician take me around the block in it. He said it stops perfectly and pedal feels normal. That plus knowing I can lock em up if I need to is good enough for me.

[Mainemantom]

Glad to see someone else doing a bench bleed on the master cylinder. Most shops I know, do not do it or don't know what I am talking about. They look at me like I am from Mars. The adjustable push rod exists too ! I thought I was going insane. I miss doing my own work.

[gadget73]

Being able to lock up the tires isn't necessarily an advantage, especially if its touchy. Once the tire stops turning, the stop distance actually increases considerably vs having it at the point just before it locks up.

people install MC's without bench bleeding? I don't tend to do it literally on the bench, but I use the little bleeder things once its bolted up and bleed the air out.