How Far Does Your 67 Brake Pedal Travel

[Kirk M.]

Just replaced my braking system with a reconditioned original power booster and MC. The brake pedal pushes almost to the floor. Is that typical using an original system? Thanks.

[John H.]

Re: How Far Does Your 67 Brake Pedal Travel

Just replaced my braking system with a reconditioned original power booster and MC. The brake pedal pushes almost to the floor. Is that typical using an original system? Thanks.

No, it's not. Did you bench-bleed the new master cylinder before installing it and then bleed the entire system to get a hard pedal?

[Kirk M.]

Re: How Far Does Your 67 Brake Pedal Travel

Yes, we bench bled the MC and bled the system. Did it cold though and I'm wondering if we should repeat with it hot. I've heard silicone bleeds better hot. Once everything is up and running like this do you just bleed at the MC? Or do you still need to bleed the lines??? Thanks.

[Tom K.]

Re: How Far Does Your 67 Brake Pedal Travel

Kirk, Make sure all connections are tight. A slight leak could be letting air in the system. Ihad to blead my 67 a lot last year when I replaced the m/c & front calipers. You may have to go all 4 wheels more than once to get agood fim pedal.
Tom

[Jim L.]

Re: How Far Does Your 67 Brake Pedal Travel

Kirk When using silicone fluid it is best to power bleed the system. You must have a sealed connection to the MC with a pressurized fluid supply. Then you should get a full pedal. Regards JR

[John H.]

Re: How Far Does Your 67 Brake Pedal Travel

Yes, we bench bled the MC and bled the system. Did it cold though and I'm wondering if we should repeat with it hot. I've heard silicone bleeds better hot. Once everything is up and running like this do you just bleed at the MC? Or do you still need to bleed the lines??? Thanks.

Bleeding at the master cylinder is useless (which is why the master cylinder bleeders were deleted later). You MUST bleed the entire system at each of the calipers as the final step in the process.

[Philip C.]

Re: How Far Does Your 67 Brake Pedal Travel

Hi Kirk Iam glad you asked and Jim 5055 said to power bleed with silicone so we may clear that up now. I was told or read it, that you should not power bleed silicone because will cause tiny air bubbles to enter the fluid. Anyone have thoughts on that? I always have trouble with power brake cars getting a good pedal. We had to jack the rear of the car up and that seemed to help. One time we had a bad brand new (rebuilt) caplier out of the box that was leaking air back in drove us nuts. Phil 8063

[Bill M.]

Re: How Far Does Your 67 Brake Pedal Travel

after replacing all calipers on my 67 i had a similar problem brakes would feel great fo 1/2 hour and then go away. it turned out to be a bad rear brake hose
Bill

[Kirk M.]

Re: How Far Does Your 67 Brake Pedal Travel

Ok. I think I need to pressure bleed the entire system at all four wheels. Here is a description I got from an earlier post:

You should bleed the entire system - this will yield the best results. You should "bench bleed" the MC before installation. This consists of using plastic plugs with rubber hose attachment nipple at the line connections- should be available at a good parts store - try the brand Lisle (and will probably have instructions). Clamp the MC in a vice, install plugs and hoses and route to the MC reservoir, fill with fluid and pump the piston until no air is returned to the reservoir.

You should jack the vehicle all four sides and crack the bleeders at all 4 wheels to let the old fluid drain out with the lines at the MC disconnected (overnight drain if not pumping will work). You can also pump them out with a bleeder pump or vacuum pump. Close off bleeders and install new MC. Bleed the farthest wheel from the MC first, then next farthest and so on. Best to have 2 people even if you are using a bleeder pump - someone to keep filing the reservoir. If you run the reservoir dry you will pull air into the line and maybe even screw up your bench bleed.

After the fourth wheel is done, I would do all 4 again starting at the farthest wheel and repeating to the next farthest.

Does that sound correct? Also, dumb question here, but what exactly am I looking for when I bleed each line? Air? Am I looking for a good constant flow of fluid with no air?

Can a local lube and brake shop do this correctly??

[John H.]

Re: How Far Does Your 67 Brake Pedal Travel

Does that sound correct? Also, dumb question here, but what exactly am I looking for when I bleed each line? Air? Am I looking for a good constant flow of fluid with no air?

Can a local lube and brake shop do this correctly??

You're looking for air bubbles in the fluid coming out of the bleeder (through a clear vinyl tube into your bleed bottle); when the bubbles stop, move on to the next caliper. Watch the fluid level in the reservoir(s) - if one runs dry, you get to do it all over again after introducing air into the system. Do the RR first, then LR, then RF, then LF; when doing the rears, do the inboard bleeder first, then the outboard.

The best sixty bucks you can spend is for a Motive Products power bleeder - makes bleeding stubborn Corvette disc brakes a piece of cake, and a one-person job that takes one trip around the car in ten minutes.