Brake line tightening down

[CopperBronco]

All this talk about fiddling with the switch is good, but sometimes they simply wear out and don’t work.
This is one of the components that we don’t hear many complaints about when people buy new parts. They usually work.
I know modern parts are a crapshoot, and maybe these don’t get replaced often enough to become an issue. But maybe it’s just time to get a new one.

I did, and I have an adjustable push rod… will extending it a bit help, or does that not solve the problem? Uncertain if this an issue of space between rod eyelet and switch? Or length of push rod?

 

[DirtDonk]

Could be an either/or kind of thing, or a combination of both.
Is your pedal height at a comfortable level at this point?
Do the brake pedal and clutch pedal sit level with each other?

 

[CopperBronco]

I just removed the bushing that goes inside the push rod eyelet and brake lights now work… don’t love the slop in the pedal, will install a new switch when I can grab one this weekend, try to install with bushing in… it’s space between switch and the push rod. This is hydratech’s push rod, and eyelet is probably just different than stock. Also my switch is bent, and it’s supposed to be flat, that’s not helping.

 

[73azbronco]

Hi, I haven't been following the whole brake upgrade, but if you are using stainless line it could be hard to get the flares to seal because stainless is harder than regular brake line. The softer line squeezes to conform together easier. As mentioned, you can check, replace, clean, or flip over the copper washers on the caliper lines. I usually reuse the copper washers with no problem. You can check the brake light switch with a test light. One wire is the hot feed, and the other wire should go hot when you push down on the pedal. I would get a quality replacement switch from Napa. Good luck

This, long time mechanic, I threw out every stainless line because of this.

 

[CopperBronco]

This, long time mechanic, I threw out every stainless line because of this.

Not using stainless… it’s steel

 

[Oldtimer]

 

[CopperBronco]

Where are exactly are you getting leaks? It sounds like it's at the calipers? And if the bleeder screws are leaking, do you have Wilwood calipers?

Todd Z.

One more problem, went to rebleed after leaks… put in new speed bleeders… one works it seems, but the passenger one leaks a ton at threads when trying to bleed. I hear Teflon tape is a bad idea as it degrades with brake fluid and is a lubricant, not a sealant. Is there a thread sealant I can use? I’m using 10 x 1.5 bleeder screws… I’ve compared to old bleeders and they seem the same… subtle change with calipers… 5/100 of an inch…

See photos, first two are the passenger one that leaks from threads when I try to bleed… other photos are driver side. Are these the GM disc brakes? Want to verify parts to verify size of bleeder screws… for all I know they are mismatched calipers and different sizes.

 

[Wild horse 75]

Bleeder screws seal on a seat. The threads do nothing for sealing. You can sometimes get a bit of dirt of the seat that prevents it from sealing. Try cranking down on it a bit more with a quality box end wrench or a socket. Oh and leaking during bleeding usually means you’ve opened the screw more than it needs to be. Bleeder screws literally just need to be cracked open.

 

[toddz69]

Are these the GM disc brakes? Want to verify parts to verify size of bleeder screws… for all I know they are mismatched calipers and different sizes.

Yes, those are the GM D52 calipers.

Todd Z.

 

[blubuckaroo]

I’m in the final stages of my hydroboost install. This is a dumb question probably, but doing full hard braking tests at idle to test for leaks.

Every time I panic stop test I get the smallest amount of residual brake fluid coming out. I’ll tighten/loosen/tighten/loosen and get it down a bit more. It will stop leaking, then do another panic test and it will leak somewhere else…

I’m only using a handheld 3/8 flare nut wrench and a brake bleeder wrench… the caliper threads tend to seep a little fluid each time I panic test, and different fittings up at master cylinder.

Wilwood told me no thread sealant, no Teflon tape, no thing, just metal to metal contact… I already cross threaded/stripped my prop valve earlier this week and had to redo.

Are there specific torque values for all these somehow? Or another way to know if too tight or too loose? Video examples are welcome as well.

Thanks in advance!

I've struggled with the same wetness around the threads on the 3/16" tubing connections. I've had some so persistent that my 3/8" tubing wrench would slip over the hex and ruin the nut. I've found that my 3/8" crow's foot on a 3/8" drive had enough backbone that it wouldn't flex and slip. I've been making a complete new brake system using steel 3/16" tubing. This stuff is pretty easy to bend but it's hard to get a double flair to seal. Next time I plan to use Ni-Cop tubing. It costs more, but it's softer and should seal better.

 

[CopperBronco]

Yes, those are the GM D52 calipers.

Todd Z.

Thanks! Looks like M10x1.5 is correct… at least that what seems like was in there… but still won’t seal… either it’s not in far enough and seating or I’ve stripped it… other one seems to be fine, and they are both in at similar distances…

 

[CopperBronco]

Anyone know how deep is too deep on these bleeders? I have one thread still above the caliper barely… either it’s not seated or I’ve stripped it.

 

[CopperBronco]

Well that’s a wrap… snapped the head off the bleeder… joys of being a brakes newbie… honestly a good thing as those caliper bleeders were leaking during panic stop testing… just old and worn out is my guess, better to find out now than while driving… any opinions on best caliper replacement that’s a quick swap? I’m running a Dana 30, has spacers to fit GM D52 calipers…

 

[CopperBronco]

Are these the GM D52s? I was searching by 1975 K5 Blazer… and are Napa reman calipers a good part? Or no? https://www.napaonline.com/en/p/ADC2225XA?impressionRank=1

 

[gnpenning]

When you go to buy the new one be sure to give a sharp eye to both the sealing surfaces. Yes take the bleeder screw out and look in the hole with a light. You probably don't have any dykem but for this a sharpie will work. Mark the end of the bleeder screw and seat. Remove and check the end to see if it is sealing. Because of the rotation you might not be able to tell where a high or low spot maybe, but you should be able to tell if it's sealing.

 

[gr8scott]

Are these the GM D52s? I was searching by 1975 K5 Blazer… and are Napa reman calipers a good part? Or no? https://www.napaonline.com/en/p/ADC2225XA?impressionRank=1

Been running those for a while now, no issues. The bleeder thread size is 3/8 - 24.

 

[CopperBronco]

When you go to buy the new one be sure to give a sharp eye to both the sealing surfaces. Yes take the bleeder screw out and look in the hole with a light. You probably don't have any dykem but for this a sharpie will work. Mark the end of the bleeder screw and seat. Remove and check the end to see if it is sealing. Because of the rotation you might not be able to tell where a high or low spot maybe, but you should be able to tell if it's sealing.

Put sharpie on end of bleeder screw? Then stick it in and try to seal, then remove and see if sharpie came off? Is that what you’re saying?

 

[CopperBronco]

Been running those for a while now, no issues. The bleeder thread size is 3/8 - 24.

Thanks! Interesting… I bought these and pulled bleeders… they were about .015” larger than the 3/8-24 speed bleeders from Dorman… wonder if since reman they re threaded holes a bit larger?

 

[CopperBronco]

Can anyone confirm these torque values?

Caliper slider pins - 17-24 ft/lbs
Caliper banjo bolt - 15-20 ft/lbs
3/8 or 10mm bleeder valve ~10 ft/lb, or 8-13 nm?

I keep leaking at the banjo & bleeder valve with new caliper… tried a bit of tighten/loosen, tighten loosen, but afraid of stripping it… my understanding is these don’t take much. Feel like I need an in person tutorial after trying all this… also what’s the max size wrench you’d use on the above bolts/fittings?

 

[gnpenning]

Put sharpie on end of bleeder screw? Then stick it in and try to seal, then remove and see if sharpie came off? Is that what you’re saying?

Yes.

Ideally marking the seat area would be best. I don't know how you could do that. Dykem you can put in the end of a swab ( not a Q tip) to cover the seat. Needs to be a thin layer. Spray dykem might also work.

You can do the same thing where your banjo fitting should be sealing. You are checking for high and low spots and complete sealing.