4 New calipers
New master
4 new rotors
All new pads
All new fluid
New booster

You’ll need to take my word that the system and master are properly bled and there definitely no air in the system. Also no leaks. Lines are good.

Pedal is still kind of soft and doesn’t have the greatest stopping power.

i was expecting a nice firm pedal and good hard stopping.

What am I missing? Could it be hoses? They look ok….

Thanks in advance

 

There is possibility that the hoses are expanding and taking some of the feel out of the pedal. If they’re original to the car there’s a very good chance they are.

You mention that you have new rotors, did you measure and set the runout within spec?

Did you follow the proper order when bleeding the calipers? Driver rear inner, outer, passenger rear inner, outer, passenger front, driver front.

I can take your word that there’s no air in the system, but it has to be something somewhere.

 

Yep, sounds like could be the rubber lines tween the calipers and the brake hard lines.

 

If the rubber lines soften, they can balloon instead of transferring the full force to the pistons & pads - (could burst when needed the most too). Most recommendations are to change them out every 10-12 years.

There is also a break-in procedure for new pads to bed them to the rotors. I forget what folks recommend, but if it wasn't in the pad manufacturer's literature a google will return the process.

 

Look like I’ll be replacing the hoses and see if that does it.

 

Did you use a pressure bleeder? If not, then do so. If so, then do so after replacing the the rubber lines.

 

You say we should trust that your brakes are air free.
But then, over the years I've read literally hundreds of threads where guys can't get all the air out of their lines.
New rotors? Generally a mistake on these cars. The old one's were fine most likely. The new ones have runout most likely.
Your brakes, inspite of this being a vintage car, should have brakes far superior to your daily driver.
Mine is 48 years old. I can put you right through the windshield, so you better buckle up!
You are clearly missing something!

 

Other than rotor runout, common problem.
Whose master? Whose Booster?
Quality USA parts?
Your pedal should be firm. Your brakes should REALLY Grab!
Quad piston calipers all the way around! Power brakes!
Think , Phoenix Reverse Bleeder!

 

You may want to consider the stainless-steel braided lines.

One other thing I have noticed. I used a power bleeder and done it with someone pumping the pedal in the car. There almost always, when you do that amount of work to the system, have small bubbles left in the system. To get it out I (carefully) drive the car. The bumps and vibrations seem to help knock those remaining air bubbles free. When I bleed the brakes again, I usually get air out of a caliper or two. I used to hit the calipers with a hammer or mallet. That works, but not as well as a drive.

 

I'll take your word for it.

But if I had trusted myself with the same job, I would have missed some air bubbles that a second round of bleeding with a Motive pressure bleeder removed. Dunno if tapping the calipers and line junctions with a wrench helped. Probably.

I'll absolutely look into the Phoenix reverse bleeder for when I need to do this again.

 

well if this is the case for me, that will come out when I replace the hoses and need to bleed again. Thanks.

 

I bled multiple times with multiple methods including the reverse bleeder. I know the air is out. But I will be re bleeding when I replace hoses so we’ll do it again lol

 

Then I'd also recommend the PTFE-lined stainless braid hoses. Though even with (new) rubber hoses, I have a firm pedal in my 79, and can lock all 4 wheels.

Did you measure your rotor runout?

 

When you buy your set of SS Braided Brake Hoses be VERY sure that they have a "D.O.T. Approved" sticker on them so they are legal on the roads of the USA. Some of the Chinese knock-offs have hit the market and they are NOT APPROVED for use on our roads and are probably not as safe as the ones approved for our use. Classic Tubing makes them and they are of a high quality and readily available for sale.

The SS Braided lines are a Big difference over the old soft rubber lines that balloon every time the brakes are used hard. When the fluid can't expand the hose it will push through a bit harder and enhance the braking action. I think the SS Braided hoses make for a better, firmer pedal.

Did you try tapping gently on the calipers and brass blocks individually while reverse bleeding them? This seems to help get any trapped air up and out of the brake fluid just a bit more effectively. On newly rebuilt calipers it might take a bit of time to fill every nook and cranny inside the caliper. They should get rid of the air on the first or second attempt at flushing reverse. I have separated the calipers in halves to allow me to rebuild them more easily. I have never had any issues with air in my brake lines ever since I bought the Phoenix Reverse Bleeder.

With the SS braided hoses and good working calipers I am also able to lock up all four wheels IF I need to. Nice solid braking!

 

I’ll also say im not impressed with reverse bleeding.

on this system in particular i think gravity bleeding followed by multiple rounds of traditional bleeding with a set of good sealing speed bleeders is the way to go. Doing this with while attaching a clear tube to the bleeder valves so you can clearly see if there is any air escaping works better than any power, vacuum, pressure, or reverse bleeding method I’ve used.

 

I don’t think I am having a rotor runout issue…. I measured with what I have.

i will probably go with stock hoses.

i wasn’t a fan of reverse bleeding… I found it more effective to gravity followed by multiple rounds of traditional bleeding with speed blenders and a clear tube. I did tap the calipers. And do a round after driving. I am confident there is no air or leaks. I think those old hoses are the culprit…. I’m hoping anyway.

 

If I was doing all that work I would go with recommended SS hoses. I think they are well worth the minor cost difference.

I made a pressure bleeder for the vette years ago (just because I did not want to wait for shipping) but now I use it on other vehicles whenever I do brakes. It just works wonderfully. When I installed the wilwoods with new SS hoses I bled them once and was done. I was pleasantly surprised. I have subsequently flushed my brake system because it makes it so easy. I recommend pressure bleeding myself.

 

Would I lie to you?

 

genuine1980,

There is always the slight possibility that during your bench bleeding process, the masters piston seals were damaged.
This event occurs often enough that LoneStar had to slap a label on the shipping boxes stating:

Do Not Force Master piston Inward More Than 1 & 3/8 inches When Bench Bleeding.
Failure to do so will void warranty.

If you think this is the issue, I can report back a lengthy way to test the masters seals.

 

You know I don’t think so…. I mean anything is possible but I was careful while bench bleeding. Once completed on the bench I installed and bled it some more with the pedal before connecting the brake lines…
if the master seals were broken, I believe I would see fluid leaking down the booster .. no?