|
I am posting because I am the end of my rope. My neighbor (and fellow goon Rivulets of Glop) owns a 2003 Chevrolet Silverado 2500HD ES, which is the extended cab with half-doors, 2WD, and an 8-foot bed. I drove him to the dealership to pick it up in the fall of ’03. It now has just under 162,000 miles on it. He loves it; it has given good service. It’s had a few issues, nothing major…until about 10-years ago, when the fuel pump went. We & four other guys pulled the bed. This exposed the nightmare, and outright criminality of (at least) GM trucks: While the body is treated with zinc, the torsion bars coated, and the entire exhaust system is stainless steel – it’s still on the factory muffler – the fuel and brake lines were made out of untreated mild steel. They were rusted, and badly, especially where they headed on up under the cab. We could’ve saved a lot of grief that day, by replacing those lines. But, it’s a work truck, and it can’t stay down that long. Three years later, the hardline from the ABS/distribution block located on the frame under the driver’s seat to the right front wheel blew while he was on the freeway at 70MPH taking his kid to hockey, emptying the master cylinder reservoir in about thirty seconds, just enough to pull off of Rt.295 at the Lawnside exit. I drove it home at 4AM on the e-brake, because his family had a serious family engagement that weekend, and he would need the truck Monday. I made a new line out of nickel tube. Bled the brakes, bing bang boom, and it was fine. Years pass. Last winter, the left front line blew, and he bought a set of stainless lines. He’s got a company van, so he could take his time this time. In April, he & his son replaced that line. And this is where we start. They couldn’t get the bleeders open due to corrosion. This resulted in four new calipers along with the pads all round. They get it done: Replace, bleed. Brakes are soft. They bled the brakes twenty-odd times. Went through four quarts of brake fluid (not pints. Quarts). Nothing, No air bubbles. No change. After I got involved, we replaced the master cylinder after we tried to pressure-bleed it & found fluid leaking at the joint between the reservoir and the cylinder case. No change. Then we learned about GM’s HydroBoost system. For unknown reasons, GM sold this truck with a hydraulic booster that runs off of the power-steering pump; there’s no vacuum amplifier. He had never serviced it (i.e. checked or changed the fluid) so since it looked like ink, and the special radiator to keep it cool rusted away ten years ago was deleted, and the fluid was never, ever changed, and the pump was making some nasty noises, we wound up replacing the power-steering pump/reservoir and the HydroBoost unit. No change to the brakes. The steering is now silky-smooth, however. Many interweb searches are occurring during this time. We learn about air being bound up in the ABS block, and that the only way to clear it is with an OBDII reader that is capable of commanding an ABS bleed. I acquire one. Perform ABS bleed; bleed left-front wheel. Bleed the whole system while we’re at it; the pressure-bleed system is a breeze. No change. Repeat eight-12-times. No change. I decide the master may be a defective rebuild. It happens. I replaced the master today: bench-bleed, all wheel bleed, ABS bleed everything. At least a half-dozen times. No change. So here’s the score: Replaced: brake lines; all four calipers; pads; rotors; master cylinder (twice!); hydroboost unit; power-steering pump. Added the correct cooler. The brakes have been bled a minimum of forty times since April. The ABS bleed function has been performed at least forty times. What happens is this: you push the brakes; at the top of the pedal travel, the brakes start to grab. Then: nothing; your foot sinks towards the floor, Then, you encounter resistance, and the brakes work fine…by now, though, the pedal is almost on the floor. And they’re consistent: Both he & I can drive it safely that way, but we both know it ain’t right, and that no one else can drive it. The only thing we haven’t replaced is the ABS unit, which I think acts also as a proportioning valve as well as the distribution block. Two lines feed into it from the master; at least three others distribute to the front wheels, and one back to the axle (I replaced that one last week when it blew during this odyssey). So: anyone have any ideas? (Edited for clarity) PainterofCrap fucked around with this message at 15:48 on Jun 16, 2021 |
#
?
Jun 15, 2021 01:50
|
|
|
|
| # ? Apr 19, 2024 20:34 |
|
|
It definitely sounds like the ABS unit is the culprit. Either the ABS bleed command isn't actually working despite telling you it is or there's air stuck somewhere that the bleed command can't get rid of.
|
|
#
?
Jun 15, 2021 15:46
|
|
|
I agree with McTinkerson, it's the only part left in the system. Did you see air bubbles during the ABS bleed? Is the parking brake adjusted?
Bulk Vanderhuge fucked around with this message at 17:34 on Jun 15, 2021 |
|
#
?
Jun 15, 2021 16:02
|
|
|
Have you confirmed the correct orientation of the new calipers? I had a buddy swap left and right which put the orientation of the bleeder on the wrong spot and left a persistent air bubble.
|
|
#
?
Jun 15, 2021 16:53
|
|
|
Try going out on some loose gravel or grass and getting abs to engage a bunch, then re-bleed?
|
|
#
?
Jun 15, 2021 17:31
|
|
|
Last ditch effort, maybe try a reverse bleeder. https://www.amazon.com/Phoenix-Systems-2104-B-Reverse-Bleeder/dp/B00GRV800S
|
|
#
?
Jun 15, 2021 22:44
|
|
|
The ABS modules themselves can fail due to rust. That may have happened here. Have either of you had the abs module actually engage during use?
|
|
#
?
Jun 16, 2021 00:08
|
|
|
StormDrain posted:Have you confirmed the correct orientation of the new calipers? I had a buddy swap left and right which put the orientation of the bleeder on the wrong spot and left a persistent air bubble. Just responded in the stupid question thread to Kastein, asking the same thing. You two are on the ball. It never even occurred to me that it could be possible to have a caliper design that could be installed in this way. You sure as poo poo can’t do that with the front calipers. It was on another forum last night that a guy had the same problem, gave up, and took it to a shop. They called him within the hour. I found the calipers nipples-down this morning, swapped them, and everything’s fine. Only took six months.
|
|
#
?
Jun 16, 2021 00:15
|
|
|
Another AI success story.  Also, those brakes are gonna be better than factory at this point.
|
|
#
?
Jun 16, 2021 00:17
|
|
|
Sure as gently caress are the cleanest lines in history.
|
|
#
?
Jun 16, 2021 01:36
|
|
|
PainterofCrap posted:Just responded in the stupid question thread to Kastein, asking the same thing. You two are on the ball. I saw him post that at about the same time, and after that I would have bet money on that being right. If it makes you feel better I feel pretty great for suggesting it.
|
|
#
?
Jun 16, 2021 04:57
|
|
|
PainterofCrap posted:
OK I came back after a moment because this part gave me pause earlier. Is this a red herring and he just had a bad bleed the first time? According to the narration it was new line, bleed, fail, new calipers. And we concluded calipers was the solution, but it doesn't answer why the first bleed didn't work. Is there a mistake in the time line, or just a failure to bleed all the way? Possible that the first bleed wasn't perfect but not as bad as the upside down calipers.
|
|
#
?
Jun 16, 2021 05:02
|
|
|
StormDrain posted:Is there a mistake in the time line, or just a failure to bleed all the way? Possible that the first bleed wasn't perfect but not as bad as the upside down calipers. Line was replaced Went to bleed, couldn't open the bleed screws due to corrosion Replaced all four calipers Problem started. I feel a mixture of, "after 45-years of working on vehicles I should have seen this right off" and "in 45-years, I've never found this to be possible" sprinkled with the elation you feel about knowing the solution. What's funny/not funny is that soooo many of these brake issue posts for these truck chassis start with, "well, the brake lines rusted out & blew, so -"
|
|
#
?
Jun 16, 2021 13:32
|
|
|
PainterofCrap posted:Sorry, I wasn't clear. I wouldn't have ever thought of it if it hadn't happened to a friend of mine. It's part of why brakes are a task where I remove and compare parts carefully. The other reason is sometimes you get the wrong part. Either the picker gets a part number wrong or the manufacturer used two styles in the same year. One of my cars was listed as "Big bore" or " small bore" and like fun I knew which one it was.
|
|
#
?
Jun 16, 2021 13:45
|
|
|
StormDrain posted:I wouldn't have ever thought of it if it hadn't happened to a friend of mine. It's part of why brakes are a task where I remove and compare parts carefully. The other reason is sometimes you get the wrong part. Either the picker gets a part number wrong or the manufacturer used two styles in the same year. One of my cars was listed as "Big bore" or " small bore" and like fun I knew which one it was. I've had this experience with brakes as well, and always, there came a point during installation when something didn't fit quite right & it gave me enough pause to sort it out. The one exception was the first time I replaced drum brake shoes & learned about leading and trailing shoes (hint: the leading shoe has a little smaller area of material - it's 'shorter' than the rear; hold them up together to compare the length of surface area on the face of the shoe) but I'm the only fossil around here still regularly servicing drum brakes. These rear calipers - they fit perfectly. I mean, the brake line union face for the hose is dead-center in the casting, so no matter the orientation, you don't have to wrestle the brake hose, and the banjo bolt & block line right up. And the pads, etc. slide right in, no offset. loving nuts. WHO DOES THAT WHO THE gently caress DOES THAT PainterofCrap fucked around with this message at 14:05 on Jun 16, 2021 |
|
#
?
Jun 16, 2021 14:02
|
|
|
The same company who’s solution to uncoated brakes lines is selling a replacement set at a discounted price of slightly coated lines. What a bitch to get it under the cab.
|
|
#
?
Jun 16, 2021 14:52
|
|
|
The other thing is the HydroBoost: it runs off of the power-steering pump. I replaced that unit, and it is identical to the one on my ‘66 Bonneville. Now, it seems to me that you’re asking a lot of a little rotary pump designed 70-years ago to run power steering & brakes on a vehicle that grosses nearly five tons. The PS cooler radiator rusted out in 2006 - when the truck was three years old. Neither of us cottoned on to the fact that it was running the brake amplifier as well, so he bypassed it. Since neither of us ever really had to change out PS fluid on the regular, we had no idea that the fluid was supposed to be changed every 40K miles or so  I installed another cooler.
|
|
#
?
Jun 16, 2021 15:57
|
|
|
PainterofCrap posted:but I'm the only fossil around here still regularly servicing drum brakes. I will still have 2 or 3 fleet vehicles with those even after the move  Actually 3 or 4, now that I think about it the RV we just got is rear drum too.
|
|
#
?
Jun 16, 2021 17:33
|
|
|
kastein posted:I will still have 2 or 3 fleet vehicles with those even after the move I'm going to have a 2021 MY vehicle soon that comes with rear drum brakes. Its not the stripped down poverty spec either. PainterofCrap posted:
My guess is that the calipers fit on something else but are in a different orientation on that vehicle. Like maybe on your friend's truck they are "clocked" at 3 on the driver side and on another vehicle they are "clocked" at 3 on the passenger side, and thus put the same part, different box and its for two different vehicles? OR........ more likely Its easier (cheaper) to make exactly the same part and drill the bleed port in one spot, turn the next part 180 degrees and drill/tap and viola, a pair of calipers for an axle.
|
|
#
?
Jun 17, 2021 00:59
|
|
|
i assume poc meant he's the only one in his friend group irl who still has drum brakes, cause there are plenty of us here on the forums with them out of four cars, the only disc brakes i own are on a shelf, to someday be installed. as such, i am not used to their wizardry and would probably make this same mistake. im glad for this thread, because thats one more thing i wont have to learn the hard way (unless i forget)
|
|
#
?
Jun 17, 2021 11:03
|
|
|
Raluek posted:i assume poc meant he's the only one in his friend group irl who still has drum brakes, cause there are plenty of us here on the forums with them That makes more sense. I only have three axles of discs compared to 5 with drums.
|
|
#
?
Jun 17, 2021 17:52
|
|
|
I just read an article that drum brakes are coming back around because of EVs and hybrids
|
|
#
?
Jun 18, 2021 01:14
|
|
|
|
| # ? Apr 19, 2024 20:34 |
|
|
 You are not alone, and apparently this can be done on Saturn Vues as well. Only reason I even thought of this suggestion was because of this thread. 
|
|
#
?
Oct 10, 2021 06:13
|
|