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dragboat
Samba Member
Joined: January 24, 2023
Posts: 26
Location: levittown NY
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 Posted: Mon Jan 15, 2024 11:13 am Post subject: residual pressure valve |
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hay guys
when i stripped my 70 karmann ghia down , the brake system , was so rusted and master cylinder seized the brakes didn't work . i ripped the lines out , pedal
assembly , master cylinder , calipers , ETC . i am in the proses of installing a 4 wheel disc system . i'm putting in a 25mm bore master cylinder . i saw the old system had no residual pressure valves in it (front disc rear drum) . do i need them ? |
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Ian Godfrey
Samba Member
Joined: September 25, 2006
Posts: 1137
Location: Melbourne Australia
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| Posted: Mon Jan 15, 2024 1:34 pm Post subject: Re: residual pressure valve |
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I have run 19 and 22mm master cylinders with disks all around with no residual pressure valves and all was good. it might be different with a 25mm master, but it should be better not worse due to moving more fluid.
Brake bleeding on these cars can be a pain, but I have 'eventually' got great brakes with pretty instant response and good pedal height.
It can also depend on the caliper chosen, some callipers pull the pistons back further than others and can benefit from a 2lb valve to keep the pistons closer to the disk. |
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dragboat
Samba Member
Joined: January 24, 2023
Posts: 26
Location: levittown NY
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| Posted: Mon Jan 15, 2024 2:05 pm Post subject: Re: residual pressure valve |
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| i see my rear calipers will mount about 11 o'clock position on the rotor . i have a double A arm suspension by imohr front and rear . the front calipers are in stock position but the rear looks like it will be higher than the master cylinder . i'm running wilwood calipers . i think the ghia needs the added braking power because of the amount of power , this STI is putting out . |
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Evil_Fiz
Samba Member
Joined: May 06, 2011
Posts: 1049
Location: Jacksonville, FL
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| Posted: Mon Jan 15, 2024 3:34 pm Post subject: Re: residual pressure valve |
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| dragboat wrote: |
| ...I have a double A arm suspension by imohr front and rear... |
Pardon the thread derailment. How is the build quality on the imohr products? I know they had some issues in the past that were being addressed. I'm asking BC I am considering it myself.
As far as the master cylinder goes, if you haven't already done so, take a look at the "Ghia Road Course Setup" thread over on Shop Talk Forums. The brakes section starts about 1/4 of the way down page 2. https://www.shoptalkforums.com/viewtopic.php?t=127619
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Emil
_________________
It's not just about what's interesting. It's also about what's helpful, and it's helpful even if it helps just one other guy working on a Ghia.
kiwighia68
See my build on TheSamba at:
The K_R_A_K_E_N_N : a 70 Ghia Convertible reinterpreted |
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dragboat
Samba Member
Joined: January 24, 2023
Posts: 26
Location: levittown NY
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| Posted: Mon Jan 15, 2024 6:51 pm Post subject: Re: residual pressure valve |
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| as far as i can see its designed well . i would have tig welded it together instead of mig , but i'm sure that would have drove the cost way up . it is put together very well . they are not 100% bolt in either . i had to modify the rear suspension to fit my requirements even. the rear body mount was eliminated . major cutting and welding to the chase in front of the horns to accept the subaru M6 STI trans , porsche axels and UV joints , to handle the subaru 450 power plant.I i read the link you provided for me . i think i'll plumb the brake system with out the residual pressure valve first and try it out . if i need one for the rear calipers can i place it just before the rear tee fitting ? |
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