Brake questions
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Senior User
Joined: Apr 2013
Posts: 477
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From: Geneva NY
Brake questions
Hey all,
My 91 Crew Cab Dually has "questionable" power assist for the brakes. I'm trying to figure it out and I'm afraid I might have.
I tested the Vacuum at the Tee on the firewall and I had 5-10. I tested it at the pump (line direct from pump to gauge) and have 20 at idle.
I was under the dash today and I noticed a slight hissing sound. I pressed the pedal by hand and it stopped for a moment before resuming the hiss. It was a press and hold, not press and release.
I'm thinking my booster is leaking. What are your thoughts?
I want to do a hydroboost swap but it isn't in the cards right now. I'd consider it if I wasn't going to have to change out the pedal too, I found a used booster for $60.
I also will be installing an old hydraulic actuated trailer brake controller and need to order a tee for the line. Is the rear line at the master cylinder for the rear brakes? I think I read it's 7/16 thread but I want to get the right part the first time.
Thanks!
My 91 Crew Cab Dually has "questionable" power assist for the brakes. I'm trying to figure it out and I'm afraid I might have.
I tested the Vacuum at the Tee on the firewall and I had 5-10. I tested it at the pump (line direct from pump to gauge) and have 20 at idle.
I was under the dash today and I noticed a slight hissing sound. I pressed the pedal by hand and it stopped for a moment before resuming the hiss. It was a press and hold, not press and release.
I'm thinking my booster is leaking. What are your thoughts?
I want to do a hydroboost swap but it isn't in the cards right now. I'd consider it if I wasn't going to have to change out the pedal too, I found a used booster for $60.
I also will be installing an old hydraulic actuated trailer brake controller and need to order a tee for the line. Is the rear line at the master cylinder for the rear brakes? I think I read it's 7/16 thread but I want to get the right part the first time.
Thanks!
i ain't rite
Joined: Mar 2005
Posts: 65,607
Likes: 5,629
From: Marlboro Mental Hospital.
remove the vacuum line to the booster and block it. see if vacuum at the tee on firewall raises or stays low. if it stays low it is somewhere else. if it raises, the booster is bad.
Thread Starter
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Senior User
Joined: Apr 2013
Posts: 477
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From: Geneva NY
Thanks for the replies guys!
Posting Guru
Joined: May 2015
Posts: 2,036
Likes: 5
Brake line fittings are a double flare fitting I believe. They have their own size. Mom and pop auto parts stores normally have exactly what you need but most importantly know what you're looking for. I never try to find weird fittings at a run of the mill auto parts store
Lead Driver
Joined: Oct 2003
Posts: 8,476
Likes: 37
From: Madison, WI
There's a reason they no longer make trailer brake controllers that depend on a hydraulic line, which runs under very high pressure and will cause you to lose your rear brakes if it fails, into the cab. Even the cheapest modern electric controller will be much safer.
Hotshot
Joined: Oct 2002
Posts: 18,488
Likes: 22
From: The Big, Oregon
Actually they stopped making them because they aren't compatible with ABS. They are a much better way to control the brakes than even a decent add-on electronic one, and far far superior to a cheapo electronic. The cheapest ones use a timer and just increase braking while the vehicle brakes are applied, the better ones have a pendulum to sense how hard you are braking, and apply the trailer brakes accordingly.
The new Ford integrated ones read the brake system pressure electronically and apply accordingly, so basically an electronic version of the tap style system.
Having towed with all three of the add on systems, I'll take a hydraulically actuated one any day. In fact I have one sitting waiting for my truck to be ready.
The new Ford integrated ones read the brake system pressure electronically and apply accordingly, so basically an electronic version of the tap style system.
Having towed with all three of the add on systems, I'll take a hydraulically actuated one any day. In fact I have one sitting waiting for my truck to be ready.
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Senior User
Joined: Apr 2013
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From: Geneva NY
Yeah I already did all my research on the brake controllers. I chose this one on purpose. Besides, a Prodigy P3 is like $200!
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Thread Starter
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Senior User
Joined: Apr 2013
Posts: 477
Likes: 0
From: Geneva NY
Brake line fittings are a double flare fitting I believe. They have their own size. Mom and pop auto parts stores normally have exactly what you need but most importantly know what you're looking for. I never try to find weird fittings at a run of the mill auto parts store
I know they're double flare. Unfortunately I've replaced plenty of lines living up here in the rust belt. Wish we had a good Mom and Pop parts house around here!
Fleet Mechanic
Joined: Sep 2016
Posts: 1,519
Likes: 224
From: Nevada
Here is one brand of alloy Brake lines.
They have it for fuel lines also.
Fedhill brake line - Where to buy brake line, fuel line, brake line flaring tools, brake line nuts and brake line fittings
Charlie
They have it for fuel lines also.
Fedhill brake line - Where to buy brake line, fuel line, brake line flaring tools, brake line nuts and brake line fittings
Charlie
Thread Starter
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Senior User
Joined: Apr 2013
Posts: 477
Likes: 0
From: Geneva NY
Yeah but that doesn't help with everyone else's cars! In the last few months I've replaced brake lines on my brother in law's Chevy, my Father in law's Dodge, my grandmother's Buick.... Oh, and bent new fuel pressure lines from 3/8 steel for that same Buick.
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