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| | | | Joined: Apr 2009 Posts: 181 'Bolter | | 'Bolter Joined: Apr 2009 Posts: 181 | I've tried a number of bleeds using both the standard bleed method as well as the 'pressure pot' method (pressure tank connected to the master cylinder)and cannot get a high pedal on the 58 Spartan I'm working on. This originally was an air over hydraulic system, which I converted to a vacuum over system, using a more modern type vacuum booster. The brakes stop well, but the pedal travel is so long that the pedal almost hits the floor. Could it be that the dual cylinders (all new/replaced) at the wheels are still trapping some air....should I try the vacuum type bleeders that are available? Your input would be much appreciated!!
1955 GMC 630, 1959 GMC W660, 1958 Chevy Spartan 80
| | | | | Joined: Mar 2004 Posts: 6,233 'Bolter | | 'Bolter Joined: Mar 2004 Posts: 6,233 | Have you adjusted the brake shoes? It should almost take two hands to turn the wheel (heavy drag) when adjusted correctly. Did you rebuild the MC? Is it the stock one or was it replaced with something newer? I like the vacuum type bleeder. Don't forget to bleed the Hydrovac first. Mike B  | | | | | Joined: Apr 2009 Posts: 181 'Bolter | | 'Bolter Joined: Apr 2009 Posts: 181 | Thanks Mike for all the ideas. I will adjust the shoes tighter, as your description is definitely tighter than I have them. The MC was professionally resleeved and I rebuilt it carefully. Hmmm. I can't remember if I bled the vac unit first, but will make sure that I do; and I will try the vacuum bleeder (a friend just gave me one)....Thanks again...
1955 GMC 630, 1959 GMC W660, 1958 Chevy Spartan 80
| | | | | Joined: Jul 2014 Posts: 48 Wrench Fetcher | | Wrench Fetcher Joined: Jul 2014 Posts: 48 | I had the same issue in my '55. It turned out that the residual pressure valve was faulty. That was seen by the ability to pump nearly 100% of the fluid out of the master, then it would refill after letting off the pedal. If you can double pump and get the pedal up to where you want it, this may be your issue. Wilwood makes an inline 10 psi residual pressure valve that works great if you need it. | | | | | Joined: Apr 2009 Posts: 181 'Bolter | | 'Bolter Joined: Apr 2009 Posts: 181 | Thanks for this info. I'm not familiar with the residual pressure valve, nor am I sure where it would fit in the hyd system, but you have me curious and I will look at the Wilwood site. Are you using a remote booster, as in my case? or is it a booster directly attached to the master cylinder?
1955 GMC 630, 1959 GMC W660, 1958 Chevy Spartan 80
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