Pettifordo Posted September 23, 2022 Report Share Posted September 23, 2022 I am rebuilding my Spitfire 1500 with a single line system on the brakes. I purchased a new clutch and brake cylinder from ANG Classic Car Parts. Bleeding the clutch was straight forward. When I have come to bleed the brakes I can’t get any fluid to leave the header tank. The master cylinder seems to be able to provide pressure (without fluid in header tank and with my thumb over the outlet hole I get some pressure build up when I depress the plunger ). Anyone seen this before ? Do I have to do something to prime the system ? What is the best way to check the inlet value ? thanks Link to comment Share on other sites More sharing options...
Pete Lewis Posted September 23, 2022 Report Share Posted September 23, 2022 sounds like the seal that closes the reservoir off is misplaced or not seating at the first touch of the pedal do make sure the pedal is fully returning to the brake switch stop position if it has a siezed pedal spindle you stop the seal from closing with foot off and the resevoir wont refill as you bleed out Pete Link to comment Share on other sites More sharing options...
johny Posted September 23, 2022 Report Share Posted September 23, 2022 yes try disconnecting the pedal completely from the master cylinder. Like this fluid should flow freely from the reservoir through the MC and out to the brakes - in fact thats how one-person brake bleeders work, either applying a pressure to the reservoir with a special cap or sucking with a small pump/syringe from the bleed nipple and no pedal operation required.... If this doesnt happen then looks like theres a problem with the MC. Link to comment Share on other sites More sharing options...
foshi Posted September 23, 2022 Report Share Posted September 23, 2022 sounds like the master cylinder single circuit brakes normally straight forward . Link to comment Share on other sites More sharing options...
Pettifordo Posted October 20, 2022 Author Report Share Posted October 20, 2022 I fixed the brakes. It seems that someone had welded an extra bit on to the top of the plunger, so that when this was installed in the master cylinder it meant that the master cylinder couldn’t travel all the way down the piston so I think that meant that the inlet value to the header tank didn’t open. No idea why PO would weld such a thing on ???? 1 Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 20, 2022 Report Share Posted October 20, 2022 we spend hours unraveling miguided myths Ha !! Pete Link to comment Share on other sites More sharing options...
johny Posted October 20, 2022 Report Share Posted October 20, 2022 1 hour ago, Pettifordo said: I fixed the brakes. It seems that someone had welded an extra bit on to the top of the plunger, so that when this was installed in the master cylinder it meant that the master cylinder couldn’t travel all the way down the piston so I think that meant that the inlet value to the header tank didn’t open. No idea why PO would weld such a thing on ???? Maybe trying to reduce pedal travel and probably did but prevents entry of fresh fluid, doh! Link to comment Share on other sites More sharing options...
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