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Another Hydrovac question #1200418 01/19/2017 3:50 PM
Joined: Aug 2010 Posts: 24 vancouver island bc J Jaredm New Guy
Jaredm New Guy J Joined: Aug 2010 Posts: 24 vancouver island bc	So I have rebuilt my hydrovac with a rebuild kit from Cadillac parts and now I have no vacuum assist, so obviously I must have put something back in incorrectly. Does anyone have any advice on how to troubleshoot these units? I would like to know where I should be looking rather than a total disassembly.

Re: Another Hydrovac question Jaredm #1200433 01/19/2017 5:41 PM
Joined: Nov 2005 Posts: 6,100 B. C. Canada 3 3B 'Bolter
3B 'Bolter 3 Joined: Nov 2005 Posts: 6,100 B. C. Canada	Hy Jaredm, do you have any brake pedal at all? Does your engine run correctly?

Re: Another Hydrovac question Jaredm #1200757 01/21/2017 11:03 PM
Joined: Aug 2010 Posts: 24 vancouver island bc J Jaredm New Guy
Jaredm New Guy J Joined: Aug 2010 Posts: 24 vancouver island bc	Brake pedal is hard and brakes work fine other than having to push as hard as possible. Engine runs and idles great. Any ideas of where to check would be much appreciated

Re: Another Hydrovac question Jaredm #1200774 01/22/2017 1:09 AM
Joined: Jun 2011 Posts: 5,096 Longmont, CO E EdPruss Crusing in the Passing Lane
EdPruss Crusing in the Passing Lane E Joined: Jun 2011 Posts: 5,096 Longmont, CO	No vacuum assist, so, check your vacuum system. Ed '37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires. '47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle. '54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed. '55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.

Re: Another Hydrovac question Jaredm #1200791 01/22/2017 2:43 AM
Joined: Nov 2005 Posts: 6,100 B. C. Canada 3 3B 'Bolter
3B 'Bolter 3 Joined: Nov 2005 Posts: 6,100 B. C. Canada	Hy Jaredm, as EdPruss said you don't appear to have vacuum assist or your atmosphere line air filter or line are plugged. Try removing the rubber hose from the 1/2" pipe on the front of the Hydrovac and trying the brakes again, if they still don't feel boosted then you may have a vacuum supply problem or a leak although you say the engine is running as it should. The other thing may be that the atmosphere valve is not opening which could be an assembly problem, good luck, hope that helps.

Re: Another Hydrovac question Jaredm #1200793 01/22/2017 2:50 AM
Joined: Aug 2010 Posts: 24 vancouver island bc J Jaredm New Guy
Jaredm New Guy J Joined: Aug 2010 Posts: 24 vancouver island bc	I have vacuum at the hydrovac, I will look at the atmosphere valve, maybe I have it in backwards or something. Thanks

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