Compensating for a Tee, Deleting the brake compensator |
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Compensating for a Tee, Deleting the brake compensator |
forrestkhaag |
Jan 23 2017, 10:40 AM
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#1
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Senior Member Group: Members Posts: 935 Joined: 21-April 14 From: Scottsdale, Arizona Member No.: 17,273 Region Association: Southwest Region |
Does anyone have the experience and time to briefly describe any needed tricks to delete the brake compensator on an early car / This, so as to make way for a 6 engine mount?
Things like / Is more brake line needed in addition to the "tee" fitting? And is the tee a hardware store item or another "porsche-priced" item that would be metric, brass, and overpriced by 3x?... (IMG:style_emoticons/default/sheeplove.gif) Sounds like a good time to change out all brake fluid as well. I have heard the warnings if one is running 914-4 brake calipers / I am not and have nice beefy 911 calipers which will do the job up front verses in back. Thanks in advance. (IMG:style_emoticons/default/beerchug.gif) |
toolguy |
Jan 24 2017, 05:53 PM
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#2
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Senior Member Group: Members Posts: 1,270 Joined: 2-April 11 From: San Diego / El Cajon Member No.: 12,889 Region Association: Southern California |
(IMG:style_emoticons/default/agree.gif) The proportioning valve is there to keep the back brakes from locking up when you need them most. When you slam the brakes, the car's weight moves forward and the rear end gets light. The proportioning valve reduces braking power to the rear as the weight transfers forward. Without the valve, the rears can lock and disaster can follow. I was having trouble bleeding the lines with the valve and considered removing it as a quick solution. Sage advice on this forum kept me from removing and, whenever I read something like Brant wrote above, I'm thankful. FWIW, this is the best explanation so far, with one clarification . . the proportioning valve does NOT reduce braking. . it LIMITS the max psi to the rear calipers. .until the proportioning valve operates, brake line psi is relatively equal front and rear. {Any difference is due to the twin valve master cylinder's design}. when the rear fluid psi reaches a factory preset level, the internal valve plunger in the proportioning valve moves and covers the fluid outlet port to the rear calipers. . Therefore no matter how hard you press the pedal, no more pressure goes to the rear calipers. . there is an external adjustment to preload the internal valve spring which regulates the valve psi cut-in pressure. . Apparently 911's didn't need such a valve, because the motor was rearward and weight transfer / lift was less noticeable. . with the mid engine 914, the tendency in hard braking for a stock suspension car is to lift the rear end weight off the rear wheels. Therefore the brakes will then tend to lockup. The non rotating wheels render the rear end to become squirrelly and tends to slid the car around sideways. Remember, brakes are most effective at the point just before lockup. . a sliding tire has no traction relative to a still spinning-braking front wheel causing an unstable skid rather than straight line braking |
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