Disc conversion help

Moose440

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Hey guys needs some help I have a 1968 Chrysler Newport and I did the willwood disc brake conversion 140-15196 I was told everything would work the way it should but my brakes will not pump up it just dribbles out and applies small amount of pressure to the front rotors I was thinking I need a new proportioning valve willwood says it’s either that or the master cylinder the car had four wheel power drum set up any help would be helpful thank you
 

Bucket

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If you are still using the original master cylinder , you will need to take the residual valve out of the master cylinder port/ports that feeds the front brakes .
 

Davea Lux

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First check the travel rod adjustment, if that is set way off you will have no pedal. Second, did Wildwood supply a replacement booster and master cylinder and if so which one? As noted, bad brake hoses that are collapsed or clogged with debris will cause a lack of flow. The proportioning valve may need to be adjusted, but be sure the travel rod is properly set prior to making the proportioning valve adjustment. A lack of flow can also be caused by a brake fitting that is not properly seated to where it sucks air every time the pedal is released. A bad seal on one of the calipers will do the same thing. Chinesium brake parts are famous for improper assembly, and poor machining so check everything carefully.

Dave
 

1970FuryConv

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For my 1990 Dodge truck, I bypassed the proportioning valve on front disc brakes. Aluminum disc brake master cylinder with original booster. Cured the truck's erratic braking. Lost the brake warning light, but NBD. I feel a brake problem long before the idiot light comes on.
 

Moose440

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So I did the master and all brake lines in the summer where is the valve in the master I need to take out and the brakes worked fine with drum set up.
 

Moose440

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And yes I did willwood hoses but they work just not right the fluid comes out but not with a lot of pressure and it holds some pressure on the rotors not a lot but makes them drag
 

Ross Wooldridge

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FWIW, While others will say that it's okay to use the drum brake booster and master you really truly need the disc brake booster and master to fully make use of your discs safely.
 

Davea Lux

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If the disks are dragging, the travel rod is set too long. Drum master should be replaced with a disc master cylinder to get enough fluid capacity to operate the disk brakes safely. As noted, you should also try to find a disk booster to get proper performance from the disc setup.

Dave
 

Moose440

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Anyone know what type of master I’m looking for and the proportioning valve that I have is fine ??
 

Davea Lux

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Anyone know what type of master I’m looking for and the proportioning valve that I have is fine ??
The C-Body dual pot disk master cylinder from '67-'73 will bolt to your booster and should work fine. As long as the proportioning valve is adjustable, that should work as well. Note that the drum booster will only provide something like 80% of the stopping power as opposed to the disk type booster.

Dave
 
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