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Tazzerblue

1970 , 1700 brake booster? Wheel cyl?

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Ok. I bought this old truck , has a box and hoist 👍 it hadn’t run in years , I got it fired up👍 . Question, how spendy is a rebuilt vacuum booster?  And can the wheel cylinders be tested before I spend the money? I may just cut the cab off and make a trailer.

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Why do you think the booster is bad?

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I just bought a hydrovac for my 75 1600 loadstar from napa for a little over 200. I bought wheel cylinder kits for all the wheel cylinders so I didn't have to remove the rusty brake lines (5 each). Now if I could get some shoes for my front brakes. I will probably have to get them relined. Thx-Ace

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can you post  part  numbers for them?  I'm trying to figure this system out. master on firewall, booster under driver  step.   maybe a photo of the new one so I could compare??  Thanks.

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Is your loadstar a single  axle or tandem? Thx-Ace

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My loadstar is a tandem,  tax axle.  I'll try and post photos I took. It burns the brake fluid. I filled both the master and the slave and when I push the brake pedal the engine accelerates.   Can the wheel cylinders be tested by putting brake fluid in the lines and then use compressed air to activate?

Second will bad points prevent good starts? I cleaned out the gas tank, installed new filters and pulled the truck until it started. It ran good for about 15 minutes, I drove it around some then I was using the hoist and it died. Wouldn't start back up. I tried again about 10 minutes late and away it went.

 

 

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Can you get some better pics of your hydrovac? My master cylinder and hydrovac look different. I also have the parts book so if you can get me the codes for your brakes from the line setting ticket I should be able to get you your part numbers. Thx-Ace

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Here is what I found online that looks similar.  This truck had a tag axle added. And on another post I had a reply that This was a valvac system, basically it looks like they piggy backed another booster with it’s own resivoir to Help with the additional axle . Where do I find the line set ticket?

04D69941-B944-4460-9CDC-5F80404741BF.jpeg

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B36A479F-0377-48B7-B215-1909646663AD.jpeg

BE8AF5A1-DB05-4D0F-BF54-AD7DE06C9A87.jpeg

9F118E34-F409-4CB2-9869-15F12AC348A2.jpeg

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Here is what I found online that looks similar.  This truck had a tag axle added. And on another post I had a reply that This was a valvac system, basically it looks like they piggy backed another booster with it’s own resivoir to Help with the additional axle . Where do I find the line set ticket?

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The line setting ticket is on the left kick pannel, below the dash, in front of the doors.

Here is what I estimated based on your pics.

Your master cyl is 55070r91. Your hydrovac is 69135r94. If so you should have code 04012 brakes on your line setting ticket. These should be available as reman.

I am unfamiliar with your velvac  49 d 4 but a quick Google search showed they are still in business so you should be fine there as well.

I Hope this helps!

 

Thx-Ace

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Here is what I found online that looks similar.  This truck had a tag axle added. And on another post I had a reply that This was a valvac system, basically it looks like they piggy backed another booster with it’s own resivoir to Help with the additional axle . Where do I find the line set ticket?

AC853FA7-0AD3-4BB1-82B2-4A58F02F11D2.jpeg

F05C9C14-4139-4E67-BF40-04D5294A3748.jpeg

3C8EFA10-C9B5-45BE-97A9-2DEC49479D57.jpeg

07745321-8994-460D-AE52-51E7C7DCB30C.jpeg

92685FB8-504E-40EB-9C5A-4A25BEAB92C6.jpeg

6077AE01-84C5-457C-A3E3-399B29D21ABE.jpeg

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21 hours ago, acem said:

The line setting ticket is on the left kick pannel, below the dash, in front of the doors.

Here is what I estimated based on your pics.

Your master cyl is 55070r91. Your hydrovac is 69135r94. If so you should have code 04012 brakes on your line setting ticket. The se should be available as reman.

I am unfamiliar with your velvac  49 d 4 but a quick Google search showed they are still in business so you should be fine there as well.

I Hope this helps!

 

Thx-Ace

Is this the line set #?

35BA019B-DC6E-407B-AB0B-B619255A6688.jpeg

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Hats off to Brake & Eq. Warehouse MPLS MN. 612-378-3141 they knew exactly what my velvac booster was, $323.00 + core. and the first booster $584.00 + core and the master had a couple of possibilities, $102-282.00.   Parts total, $1100 give or take  a couple hundred .plus tax..              Wheel cylinders 50-100.00 each X 12 if I need all or any???                                        I think I will make it into a trailer... 

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Your pic is not the line setting  ticket. The line setting ticket will have a list of components and related codes the truck was built with.

The prices you posted seem high. I replaced the hydrovac and rebuilt the wheel  cylinders on my 74 1600 for less than $400.

Thx-Ace

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Here are some  pics of my components. I checked and all the parts cost me less than $300. I need to check the master cylinder and bleed everything again. If I have to rebuild my master cylinder it will be right at $300 for everything.

Here is my master cylinder  and hydrovac.

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tmp_10873-20190509_185213504846428.jpg

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This is where your line setting ticket should be. Someone removed this one before I bought this truck... Thx-Ace

tmp_10873-20190509_184925519643010.jpg

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There is nothing on the lower panel..  We have different master and booster, and I have the second booster with master attached for the tag axle.  Where did you buy yours I can check with them.

Thanks, for your help.. Have a good weekend..

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Well, I'm still searching for parts or changing the system to a double booster, chevy used a double booster.. The truck I have was streached and a tag axle added. Which is why the velvac 49D-4 was added. I traced the brake lines and the original system now controls the back 2 axles and the velvac now controls the front axle.  So I'm thinking that a factory tandem or twin screw would have had a different system. like  the double booster.   

Anyone know more about this double booster? or have a twin screw or tandem with hyd brakes? 

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I got my parts at my local napa. It's locally owned and they are great. Good luck finding a parts store that still knows how to look up parts that re not in the computer...

II think the napa number was 80-5004. It is different than yours but might replace your hydrovac.

According to my parts book a factory tandem axle loadstar would use hydrovac numbers 67 216c91, 3156091, or 419168c91. These are tandem boosters, not dual. Tandem boosters have two vacuum canisters and one slave cyl in one unit. school buses used a dual system which is different.

You need to diagnose your problem before looking for parts. Unfortunately there are not that many people left who are good at working on hydrovac systems. I had to learn to keep my own trucks running, or stopping.

Here is a link to a helpful document.

https://www.google.com/url?q=http://www.dspartscompany.com/DocumentsCenter/Hydraulic%20Brake%20edit.pdf&sa=U&ved=0ahUKEwjp2KuCy6viAhXNmq0KHXsIATkQFggeMAg&usg=AOvVaw20o_38QQUJGWx4UK5hqSPW

You might consider starting a topic, diagnosing hydrovac brake problems.

Thx-Ace

 

 

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Two other places to look for the line set ticket. Sometimes pasted to the sun visor or back side of the glove box lid.

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