Brake bleeding & hair pulling
Thread Starter
Instructor
Joined: May 2021
Posts: 225
Likes: 73
From: Missouri
The saga continues. I put a crimped line on the rear MC port. Pedal is much firmer now. Not great but definitely better. Went for a quick test drive. Pedal is firm but still somewhat spongey and it took a lot of travel and effort to lock the fronts up but they did lock. So seems like the rears are definitely the bigger problem. I’m going to go ahead and put a crimped line on the front MC port as well just to see what I get. I should have a really firm, zero sponge with both ports plugged correct?
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 9,137
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From: US-PNW
The saga continues. I put a crimped line on the rear MC port. Pedal is much firmer now. Not great but definitely better. Went for a quick test drive. Pedal is firm but still somewhat spongey and it took a lot of travel and effort to lock the fronts up but they did lock. So seems like the rears are definitely the bigger problem. I’m going to go ahead and put a crimped line on the front MC port as well just to see what I get. I should have a really firm, zero sponge with both ports plugged correct?
I think you're experiencing a somewhat normal sequence of events. Bleed it until you get a pedal that safely stops the car, then drive it a bit to "shake" the bubbles loose. Bleed again; drive again; bleed again. By the third cycle you should have a good, long-lasting, firm pedal.
To mimic the vibration from driving, a lot of folks hit the calipers with a plastic mallet to dislodge bubbles during the bleeding process.
Thread Starter
Instructor
Joined: May 2021
Posts: 225
Likes: 73
From: Missouri
Ok just got done testing with crimped lines on both MC ports. Was rock hard even with boost. At least until the pressure blew past my crimp 😝. So it’s confirmed the MC is fine.
I did put in a new proportioning valve. I didn’t see any mention in the service manual for bleeding it tho. Anything special you guys do with it or just move on the bleeding the lines again?
I did put in a new proportioning valve. I didn’t see any mention in the service manual for bleeding it tho. Anything special you guys do with it or just move on the bleeding the lines again?
Safety Car
Joined: May 2001
Posts: 4,759
Likes: 1,647
From: Fairfax Virginia
The "other way" of doing it is to use a Phoenix Reverse Brake Bleeder and PUSH the air UP and out instead of trying to Force it to go down. It works really well and is less expensive then a lot of the pressure bleeders. My Motive Bleeder is sitting on the shelf as all the hoses have crumbled away after being used a couple times.
After rebuilding the calipers on my C3 I used the Phoenix Reverse Bleeder to get rid of ALL the air trapped in the crevices inside the calipers and brake connections. It is also really handy if and when you have a Hydraulic clutch to bleed. The clutch on our Chevrolet Pickup could only be done using the Phoenix system because of the way it is mounted. The Hydraulic Clutches on the C4's and on are a lot easier with this tool.
The Phoenix V-5 bleeder is only $55 on Amazon and will help you the rest of your days making bleeding simple like it should be. This one tool can do the following methods: Reverse, Vacuum, Pressure and Bench Bleeding of the master cylinder. It is my Go-To tool for any bleeding operation. I have used it on my Corvettes, Boat, RV, motorcycle and even on my Cessna 172 and the one tool made it easy work to boot.
Best regards,
Chris
After rebuilding the calipers on my C3 I used the Phoenix Reverse Bleeder to get rid of ALL the air trapped in the crevices inside the calipers and brake connections. It is also really handy if and when you have a Hydraulic clutch to bleed. The clutch on our Chevrolet Pickup could only be done using the Phoenix system because of the way it is mounted. The Hydraulic Clutches on the C4's and on are a lot easier with this tool.
The Phoenix V-5 bleeder is only $55 on Amazon and will help you the rest of your days making bleeding simple like it should be. This one tool can do the following methods: Reverse, Vacuum, Pressure and Bench Bleeding of the master cylinder. It is my Go-To tool for any bleeding operation. I have used it on my Corvettes, Boat, RV, motorcycle and even on my Cessna 172 and the one tool made it easy work to boot.
Best regards,
Chris
Thread Starter
Instructor
Joined: May 2021
Posts: 225
Likes: 73
From: Missouri
Well after testing the MC as good, I noticed the bleeders on the refurbed calipers still weeping. I think these calipers are junk. Bleeding should not be this difficult. At this point im going to send the calipers back. I have really put some torque on the bleeders and yet they are still weeping after a test drive. I may just spend the money and get some new Willwoods and screw the rebuilt ones. I’m spent….
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
sci85
I don't believe buying aftermarket calipers is a cure-all. In fact, it may add to more issues. The Delcos are fine once you work the bugs out.
Typhically, rebuilt calipers don't leak at the bleeder locations, but rather at the two halves joint seals or piston seals. So, I think the bleeder screws are to blame here.
The bleeder screw quality in local parts stores seem to be hit and miss. I ended up buying 10 from three different stores. The threads are always questionable, more specifically, too sloppy. That's likely why yours leaked.
Also, the bleeder screws should have a taper on the tip. Those seats itself with the flare inside the caliper.
The proportioning valve does not get bled directly but rather indirectly.
When I advised you to make some MC test lines, that procedure is strictly for a vehicle with the engine off, sitting in the garage. By no means are the test lines for a road test because of only half your braking is available. A wise man uses the two test lines at the same time to receive instant results about the MC and to avoid additional bleeding of the system.
I don't believe buying aftermarket calipers is a cure-all. In fact, it may add to more issues. The Delcos are fine once you work the bugs out.
Typhically, rebuilt calipers don't leak at the bleeder locations, but rather at the two halves joint seals or piston seals. So, I think the bleeder screws are to blame here.
The bleeder screw quality in local parts stores seem to be hit and miss. I ended up buying 10 from three different stores. The threads are always questionable, more specifically, too sloppy. That's likely why yours leaked.
Also, the bleeder screws should have a taper on the tip. Those seats itself with the flare inside the caliper.
The proportioning valve does not get bled directly but rather indirectly.
When I advised you to make some MC test lines, that procedure is strictly for a vehicle with the engine off, sitting in the garage. By no means are the test lines for a road test because of only half your braking is available. A wise man uses the two test lines at the same time to receive instant results about the MC and to avoid additional bleeding of the system.
Thread Starter
Instructor
Joined: May 2021
Posts: 225
Likes: 73
From: Missouri
I hear ya Headsup. Lone star suggested trying some new bleeders as the ones that shipped originally also were weeping. The fronts seem to be fine the rears not so much. I’ll try return the rear calipers on their suggestion and see where that goes. If that fails, I’ll bite the bullet and get some Willwoods as the MC is testing out good. I can’t think of anything else to try at this point so can’t hurt.
Last edited by sci85; Apr 23, 2022 at 09:30 PM.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Maybe someone that has Wilwoods will chime in here, but rumor is that the rear calipers have to be removed to bleed them? Then installed due to the location of the bleeder port?
Is that something you would be interested in doing every time?
Is that something you would be interested in doing every time?
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Thread Starter
Instructor
Joined: May 2021
Posts: 225
Likes: 73
From: Missouri
No I wouldn’t but what else to do? I did the two crimped lines on the MC and it was fine. Would hardly move. I’ve bled them to death. Fluid flows thru all the lines just fine. I guess I could try reverse bleeding but I’m just stuck on where to go from here.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
At this point, and going back over the previous post;
Keep in mind that any ill-fitting bleeder screws that are weeping DOT3 will also allow air back into the caliper every time the brake pedal returns.
I can't prove anything yet, but I suspect maybe the Prop Valve is jammed rearward, hindering the rear brakes useless.
Its designed to closed off either system if it detects a leak. Which you have because of the inferior bleeder screws?
I also will assume all four rear bleeders not only opened ok, but closed ok? Or are the four rears weeping?
If you click on my profile, then go to photo albums about Prop Valves you will see the innards of the valve and a special tool ($10) to hold the PV piston while doing brake work.
In my opinion, just throwing new parts at this issue will just add to frustration$$$$$$ later.
Regroup-rethink, you will get it.
Keep in mind that any ill-fitting bleeder screws that are weeping DOT3 will also allow air back into the caliper every time the brake pedal returns.
I can't prove anything yet, but I suspect maybe the Prop Valve is jammed rearward, hindering the rear brakes useless.
Its designed to closed off either system if it detects a leak. Which you have because of the inferior bleeder screws?
I also will assume all four rear bleeders not only opened ok, but closed ok? Or are the four rears weeping?
If you click on my profile, then go to photo albums about Prop Valves you will see the innards of the valve and a special tool ($10) to hold the PV piston while doing brake work.
In my opinion, just throwing new parts at this issue will just add to frustration$$$$$$ later.
Regroup-rethink, you will get it.
Thread Starter
Instructor
Joined: May 2021
Posts: 225
Likes: 73
From: Missouri
I appreciate the optimism Headsup. I grabbed some new bleeders yesterday and they were worse than the originals. So yes, all 4 were weeping. Not a lot but enough to have a bit of fluid on it. I suspected the valve as well so I cracked that rear line open while pressure bleeding and it was flowing just fine. No light on either. At this point I think I will return the rears. Already called lone star and that was their suggestion. More down time ugh.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Do you realize there is a "special ward" or wing at the hospital for C3 owners?
The patients walk the halls with their *** hanging out the back of their gown, pushing a I.V. cart with one hand and in the other is a handful of bleeder screws.
And in the dangling I.V. bag is DOT3, running through their veins.
The patients walk the halls with their *** hanging out the back of their gown, pushing a I.V. cart with one hand and in the other is a handful of bleeder screws.
And in the dangling I.V. bag is DOT3, running through their veins.
Le Mans Master
Joined: Jan 2001
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I went to Wilwoods almost 10 years ago. Not a problem since. I recommend them. Supposedly I was supposed to tilt them up to properly bleed them but never got around to it. They've been great. Before that I'd would have to work on my brakes all the damned time... probably at least once per year...and that had been going on for like ever.
I got them on group sale from Van Steel that was on here and I almost didn't because even at that they were expensive even then. I am really glad I did it now. Haven't had a brake problem since. I got the D8-6 fronts and D8-4 rears kit with SS hoses (in red just because group sale). If I was getting them now I'd probably just get the D8-4s with SS hoses in the Dark Gray Hard Anodized.
FYI
http://www.vansteel.com/index.cfm?fu...&subgroup=1962
I got them on group sale from Van Steel that was on here and I almost didn't because even at that they were expensive even then. I am really glad I did it now. Haven't had a brake problem since. I got the D8-6 fronts and D8-4 rears kit with SS hoses (in red just because group sale). If I was getting them now I'd probably just get the D8-4s with SS hoses in the Dark Gray Hard Anodized.
FYI
http://www.vansteel.com/index.cfm?fu...&subgroup=1962
I hear ya Headsup. Lone star suggested trying some new bleeders as the ones that shipped originally also were weeping. The fronts seem to be fine the rears not so much. I’ll try return the rear calipers on their suggestion and see where that goes. If that fails, I’ll bite the bullet and get some Willwoods as the MC is testing out good. I can’t think of anything else to try at this point so can’t hurt.
Thread Starter
Instructor
Joined: May 2021
Posts: 225
Likes: 73
From: Missouri
It’s an option on the table if swapping out the rear calipers doesn’t improve it. I did notice some weeping at the lines going into the p-valve so I re-tightened those lines as well as the others real good. I’m going to next pull the pads from the rears and move the pistons in and out and make sure they look good and nothings jacked up and maybe if there’s still a little air in there that will lodge it out. I’m also going to take a sharpie and draw a line across the rotor so when I go for a test drive and I can see if the pads are actually gripping the rotor with any force. It’s raining today so that will have to wait until tomorrow.
Appreciate all the suggestions and will report back after further tests.
Appreciate all the suggestions and will report back after further tests.
Tech Contributor
Joined: Aug 1999
Posts: 15,175
Likes: 3,990
From: Connecticut, USA
Clay
I use the motive to test for leaks. I put on the circuit to check/bleed and pump it up to 10-13 lbs. Watch the gauge, it should not drop. If it does, weeping calipers, leaking calipers, hose to block leaks, line leaks. When I did my 72 15 years ago, there was a slight leak at one of the rear connections, I don't recall but it showed on the Motive gauge, I had to jump on the connection to seal it. That was with new SS lines.
The QC on some rebuilt items is poor, hopefully that is not your issue but I wouldn't be surprised.
Gary
I use the motive to test for leaks. I put on the circuit to check/bleed and pump it up to 10-13 lbs. Watch the gauge, it should not drop. If it does, weeping calipers, leaking calipers, hose to block leaks, line leaks. When I did my 72 15 years ago, there was a slight leak at one of the rear connections, I don't recall but it showed on the Motive gauge, I had to jump on the connection to seal it. That was with new SS lines.
The QC on some rebuilt items is poor, hopefully that is not your issue but I wouldn't be surprised.
Gary
Tech Contributor
Joined: Aug 1999
Posts: 15,175
Likes: 3,990
From: Connecticut, USA
I sure do, today I checked another diff and this time someone broke a tap in the bottom hole where the strut rod bracket bolts up. Then they drilled off the broken tap and tapped a smaller hole to hold the bracket on I guess. I threw it out.
Racer
Joined: Nov 2019
Posts: 336
Likes: 173
From: Canadian living in southern France
This is true. I put Wilwoods on the rear, and the only way to get them bled properly was to remove the callipers, use a bunjy cord to hold them vertical, and then I jury-rigged some adapters to bleed them from the bottom bleeder screw. So I guess, reverse bleeding. Up until I did this, after days of work and like the OP, lots of hair pulling, I couldn't get a hard pedal.
Thread Starter
Instructor
Joined: May 2021
Posts: 225
Likes: 73
From: Missouri
This is true. I put Wilwoods on the rear, and the only way to get them bled properly was to remove the callipers, use a bunjy cord to hold them vertical, and then I jury-rigged some adapters to bleed them from the bottom bleeder screw. So I guess, reverse bleeding. Up until I did this, after days of work and like the OP, lots of hair pulling, I couldn't get a hard pedal.