Front Brake Upgrade Makes Soft Pedal - Page 6

Twoxentrix · 05-15-2018, 04:21 PM

We all know, communicating "the issue" to others can be a task in itself, but just reading your experience(s) with all this makes ME frustrated!
Solution may just well be to put yourself in the passenger seat with the Tech driving, as he descends down a hill. Then, after his heat rate calms & the color comes back to his face, he may have a different perspective.
I'm feeling your pain & hope you get resolution soon

carringb · 05-15-2018, 05:24 PM

Also possibilty: That dealer never trained their techs on proper brake bleeding, so all the diesels do come out feeling that way

REF · 05-17-2018, 02:20 AM

Vacuum booster aside.....have you considered the lines to be the culprit? I had a shop up in Loveland make me all new braided SS brake lines with new fittings when it was up at CCV a while back getting some other undercarriage and brake work done. I brought them all the old assemblies to copy.
You’d think you would see fluid, but I those old lines get weak and can sometimes swell or hide cracks inside the casing that go undetected, worth a shot at this point.

'03 Ford E350 7.3L Diesel
SMB RB50 w/CCV top
Quigley 4X4 w/Deavers & Agile RIP kit

jage · 05-17-2018, 09:19 AM

So I got the van back.

It's better, it's not 1000% or anything but I believe we are in the realm of hopeful.

On tuesday I went over and rode around with the tech for a literal hour in the lot. Up down back and forth, both him and me. It was all over the map as usual but it seemed to improve when he ran the HCU purge- it's pretty intense compared to just slamming the brakes and firing the ABS on ice or whatever.

Anyway the HCU purge seemed to make things better, so he did it 3 more times. Then it seemed worse. Then I realized it felt amazing going up a slight incline (parking lot tier like 1º) and awful going down the same incline. It makes no sense, I mean a closed hydrolic system shouldn't respond to angle and a few degrees at most absolutely should be undetectable, but I swear you could have blindfolded me and I would be able to tell you if it was uphill or down at that point, just based on the pedal feel.

We also discussed the brakes and despite being about six months since the upgrade I probably haven't broken them in. Yeah it hasn't exactly been fun to drive. In any case he noted there is still some cross hatching and I'm sure they aren't broken in- I'll come back to that in a second.

I left it with him with instructions to bleed it (purge the air that maybe purged from the HCU purge into the line) and then run the HCU purge again. Incidentally there was no information in the shop manual about how to bleed the HCU, it just said "see components" and components only listed the calipers.

Anyway, it stayed there overnight again and ALL of the next day. I started to wonder if him having bled it gave him an epiphany or something. I literally picked it up at 5 minutes to close after almost everyone had gone home. The only thing on the paper was the bleed, some fluid and the most expensive parking lot ride ever- HAHA I was happy to pay it though because I know from riding around with him that he did due diligence and triple checked everyone elses' work, then looked again for anything that could be causing problems. I probably got off light.

In any case I got in and the pedal was freaking spongy as heck.You think I'd Krakatoa over that but I didn't, it felt better. Why? Well driving it home I realized that we are now firmly in the area of breaking in the pads. It's totally consistent, no longer a pants crapper randomly and yes it's noodle soft, but it is consistent and in line with exactly what I'd expect from new pads.

So the next thing to do is drive it 500 miles, which will put me outside of Kansas City since I no longer have time to just toodle around.

In any case the pedal does still drop slowly all the way to the floor, but that's minor now compared to the overall consistency and it now for the first time feeling like "breaking in the brakes".

Thanks for all the support, I will update once there are some miles on it and circle back around to the dropping pedal because I sure as heck don't want to be nose down a 2' ledge holding it in lo and having the pedal go on vacation... on the way to Indiana however that should not be an issue.

MountainBikeRoamer · 05-17-2018, 09:47 AM

Rock on!!

For sure bedding-in pads can be mushy as heck for a while (usually more so on drum brakes where the curvature of the pads doesn't match the curvature of the inside of the drum), but awesome to hear there's progress!

Hey. In case you're still not seeing it firm up to your liking after you've piled on the miles --- don't rule out that brake booster.

Interesting thread here on the H.A.M.B. (Jalopy Journal.) While typically a failing booster results in a *firmer* pedal (with less braking force available), it's not necessarily always the case....depending on the internal design of a brake booster's vacuum chamber arrangement, it sounds like certain types of failing boosters (vac leaks or valve issues) can indeed cause a sinking pedal.

CAN A BAD BRAKE BOOSTER CAUSE A LOW PEDAL SITUATION?
https://www.jalopyjournal.com/forum/...uation.182180/

A brake booster can be checked for pressure integrity.

In any event --- safe travels and congrats!!

Nrobert10 · 05-17-2018, 09:59 AM

If the pedal doesn’t firm up after pad breakin I would second looking at the hoses. They might not leak but as they age they can get softer and swell under pressure. New hoses might be the ticket. Braided would be the best but costly.

Good luck I hope it’s cured!

jage · 05-25-2018, 07:23 AM

So 19.4 miles later and the brakes feel way way better. I did hit a yellow and crammed down harder and there was still that squish but it still felt in line with the pads breaking in.

The HCU and bleed arms to have done the trick, will update if I ever get out of here and can put some miles on!

karma · 05-25-2018, 12:11 PM

Time for a Hydroboost swap, if you wanna complicate it more

MadScience · 05-25-2018, 09:00 PM

Good to hear that this is finally heading in a better direction!!

I've done the ABS pump activations on other vehicles, and yes, the pump really cycles a bunch more than even a couple panic stops on snow/ice would provoke.

jage · 06-06-2018, 09:09 PM

1500 mile update.

Brakes are good, still not 100% happy with the feel, but the function is fine. In fact they've already paid for themselves, thanks to a single bulb minivan with smoked out covers on the interstate. Going from full speed (60mph) to a line of cars at full stop is no fun with the best of information but the the single bulb was on the sun side, and I took it for a glint and barely reacted in time.

The lone light was so bad I had another half a dozen hard stops before getting away from the minivan; even with full attention it was hard to read. In any case safe and happy is worth all the service nightmares, thank goodness the castle rock dealer finally got things right.