Brake Fluid Pressure

[Peter Roberts]

OK Gents, The puzzle continues. Having rebuilt the Master Cylinder with a kit from Abingdon Spares, I still cannot get fluid to the wheel cylinders. When I disconnect lines at a front brake hose and then at the rear brake hose, I can get a flow of fluid. But, when I reconnect, I cannot get fluid up to the wheel cylinders. This afternoon, I had my Trusty Assistant pump while I held my finger over a disconnected line. The pressure could not move my finger (i.e. with little effort I could stop the flow of fluid). When I took my finger off, fluid flowed. Seems to me that there should be more pressure than this. I expected the pumping to force fluid past my finger. What think you? If the pressure is too low, then is the problem in the MC? The piston and its rubber fit very snugly....no corrosion in the cylinder. Reassembly was checked extra twice for correctness. Madhu mentioned that in some of the rebuild kits the washer that fits at the end of the cylinder is too thick. How would this cause my problem? Is something else going on? Since the system is virtually empty of fluid, would the air cushion cause the pressure to be this low? Your thoughts would be most appreciated. _Peter

[Bill Traill]

> OK Gents, > > The puzzle continues. Having rebuilt the Master Cylinder with a kit > from Abingdon Spares, I still cannot get fluid to the wheel cylinders. >

Peter, Possibly something blocking the pipes? My experience with blocked brake pipe...... My TC brake pedal froze while making a U-turn. Pedal solid as a rock, no brakes and no give what so ever, but let-up and re-apply and all was ok. Happened again on the remainder of the run home. I removed the master cylinder. A glob of rubber was blocking the MC banjo bolt. The back flow of fluid moved the glob clear when I lifted my foot, and then I had several good brake applications until it worked it's way back to the bolt. The culprit was a disintegrated rubber washer; the thick one that goes all the way down in the MC barrel. The MC was rebuilt five years prior. I have used silicone brake fluid for 30 years and wonder if the last MC kit had an incompatible rubber washer. All other internal soft parts were in excellent condition. Bill Traill TC 5221 Santa Clara, California. US

[Mark Stolzenburg]

Peter, Have you tried to bleed your brakes as or yet? With all of the bleeder screws closed with the exception of the right rear do you get fluid to the right rear? If you haven't bleed the brakes as of yet I would do that first. Make sure you start with the right rear. Make sure all bleed screws are closed. Then open the right rear (have a clear tube attached in a jar with some fluid at the bottom) and have your trusty pumper push down on the pedal. At the bottom of the stroke close the bleed screw and have your pumper release the pedal. Do this process until you have clear brake fluid with no bubbles. Work your way clockwise around the car. Without bleeding the brakes entirely you are compressing air in the lines and end up with a soft pedal or no pedal. When I bleed the brakes on my TC I noticed the system was really sensitive to air in the system (more so than other vehicles) and I could not get a hard pedal until all brakes were bleed. Hope this helps! Mark Stolzenburg St. Louis, Missouri TC 7812

----- Original Message ----- From: "Peter Roberts" mgtc@comcast.net> To: mg-tabc@yahoogroups.com> Sent: Wednesday, May 18, 2005 2:53 PM Subject: [mg-tabc] Brake Fluid Pressure > OK Gents, > > The puzzle continues. Having rebuilt the Master Cylinder with a kit from > Abingdon Spares, I still cannot get fluid to the wheel cylinders. > > When I disconnect lines at a front brake hose and then at the rear brake > hose, I can get a flow of fluid. But, when I reconnect, I cannot get fluid > up to the wheel cylinders. > > This afternoon, I had my Trusty Assistant pump while I held my finger over a > disconnected line. The pressure could not move my finger (i.e. with little > effort I could stop the flow of fluid). When I took my finger off, fluid > flowed. Seems to me that there should be more pressure than this. I expected > the pumping to force fluid past my finger. What think you? > > If the pressure is too low, then is the problem in the MC? The piston and > its rubber fit very snugly....no corrosion in the cylinder. Reassembly was > checked extra twice for correctness. Madhu mentioned that in some of the > rebuild kits the washer that fits at the end of the cylinder is too thick. > How would this cause my problem? > > Is something else going on? Since the system is virtually empty of fluid, > would the air cushion cause the pressure to be this low? Your thoughts > would be most appreciated. > > _Peter > > > > > Yahoo! Groups Links > > > > > >

[Paroor]

Dear Peter Roberts, I am of the same opinion of Bill Traill. There must be some blocking. Recently I heard a story from BENZ truck service department. The new big truck while pulling up the Alps got stuck in a pass. So they reported the matter to the service department. After while engine started. But this happened again few times in the same place while pulling up 12% climb. The team of Engineers/Technical staff came to the spot for investigation. Benz had to spent a lot money to reload the cargo to some other truck and also had to suffer the investigation cost over a million Euro. They got the point after a long investigation. The fuel (diesel) tank is fixed in the rear. The fuel supply rubber pipes ( shorter length )are inter connected with a metal pipe link. While assembling the fuel pipe in the factory, the metal link cut the inner part of the rubber pipe. This cut rubber part remained in place and was acting like a "Flap" or Valve. While driving in the plain the fuel flow was less. Pulling up the Alps at 12% climb they needed maximum fuel supply at max. RPM. May be the tilted position of the rubber pipe also influenced the " Flap" to stop the fuel supply. Hence the engine starved. It was such a small mistake in assembly section, resulting in such a failure. There are members, disliking me writing such stories. I am sorry! This is not a true TC problem. But one can learn. Madhu -----Urspr ngliche Nachricht----- Von: mg-tabc@yahoogroups.com [mailto:mg-tabc@yahoogroups.com]Im Auftrag von Peter Roberts OK Gents, .......... When I disconnect lines at a front brake hose and then at the rear brake hose, I can get a flow of fluid. But, when I reconnect, I cannot get fluid up to the wheel cylinders. .......... Is something else going on? Since the system is virtually empty of fluid, would the air cushion cause the pressure to be this low? Your thoughts would be most appreciated. _Peter

[Paul Camp]

Keep writing Madhu makes interesting reading if anyone objects they can use the delete key paul TC3348

----- Original Message ----- From: "Paroor" paroor@t-online.de> To: "Peter Roberts" mgtc@comcast.net>; mg-tabc@yahoogroups.com> Sent: Thursday, May 19, 2005 6:59 AM Subject: AW: [mg-tabc] Brake Fluid Pressure > Dear Peter Roberts, > I am of the same opinion of Bill Traill. There must be > some blocking. > > Recently I heard a story from BENZ truck service department. The new big > truck while pulling up the Alps got stuck in a pass. So they reported the > matter to the service department. After while engine started. But this > happened again few times in the same place while pulling up 12% climb. The > team of Engineers/Technical staff came to the spot for investigation. Benz > had to spent a lot money to reload the cargo to some other truck and also > had to suffer the investigation cost over a million Euro. They got the > point > after a long investigation. The fuel (diesel) tank is fixed in the rear. > The > fuel supply rubber pipes ( shorter length )are inter connected with a > metal > pipe link. While assembling the fuel pipe in the factory, the metal link > cut > the inner part of the rubber pipe. This cut rubber part remained in place > and was acting like a "Flap" or Valve. While driving in the plain the fuel > flow was less. Pulling up the Alps at 12% climb they needed maximum fuel > supply at max. RPM. May be the tilted position of the rubber pipe also > influenced the " Flap" to stop the fuel supply. Hence the engine starved. > It > was such a small mistake in assembly section, resulting in such a failure. > > There are members, disliking me writing such stories. > > I am sorry! This is not a true TC problem. But one can learn. > > Madhu > > > -----Urspr ngliche Nachricht----- > Von: mg-tabc@yahoogroups.com [mailto:mg-tabc@yahoogroups.com]Im Auftrag > von Peter Roberts > > OK Gents, > .......... > When I disconnect lines at a front brake hose and then at the rear brake > hose, I can get a flow of fluid. But, when I reconnect, I cannot get > fluid > up to the wheel cylinders. > .......... > > Is something else going on? Since the system is virtually empty of fluid, > would the air cushion cause the pressure to be this low? Your thoughts > would be most appreciated. > > _Peter > > > > > > > Yahoo! Groups Links > > > > > >

[Geach, Nigel (Crofton)]

Madhu, Keep it up! I, for one, find your stories fascinating and educational. The shared knowledge helps us all. Cheers from cloudy Vancouver Island, Nigel '46 TC 0710 '73 Triumph Trident 750 -----Original Message----- From: mg-tabc@yahoogroups.com [mailto:mg-tabc@yahoogroups.com] On Behalf Of Paroor Sent: Wednesday, May 18, 2005 11:00 PM To: Peter Roberts; mg-tabc@yahoogroups.com Subject: AW: [mg-tabc] Brake Fluid Pressure Dear Peter Roberts, I am of the same opinion of Bill Traill. There must be some blocking. Recently I heard a story from BENZ truck service department. The new big truck while pulling up the Alps got stuck in a pass. So they reported the matter to the service department. After while engine started. But this happened again few times in the same place while pulling up 12% climb. The team of Engineers/Technical staff came to the spot for investigation. Benz had to spent a lot money to reload the cargo to some other truck and also had to suffer the investigation cost over a million Euro. They got the point after a long investigation. The fuel (diesel) tank is fixed in the rear. The fuel supply rubber pipes ( shorter length )are inter connected with a metal pipe link. While assembling the fuel pipe in the factory, the metal link cut the inner part of the rubber pipe. This cut rubber part remained in place and was acting like a "Flap" or Valve. While driving in the plain the fuel flow was less. Pulling up the Alps at 12% climb they needed maximum fuel supply at max. RPM. May be the tilted position of the rubber pipe also influenced the " Flap" to stop the fuel supply. Hence the engine starved. It was such a small mistake in assembly section, resulting in such a failure. There are members, disliking me writing such stories. I am sorry! This is not a true TC problem. But one can learn. Madhu -----Urspr ngliche Nachricht----- Von: mg-tabc@yahoogroups.com [mailto:mg-tabc@yahoogroups.com]Im Auftrag von Peter Roberts OK Gents, .......... When I disconnect lines at a front brake hose and then at the rear brake hose, I can get a flow of fluid. But, when I reconnect, I cannot get fluid up to the wheel cylinders. .......... Is something else going on? Since the system is virtually empty of fluid, would the air cushion cause the pressure to be this low? Your thoughts would be most appreciated. _Peter Yahoo! Groups Links

[Gene Gillam]

Peter wrote:

>The pressure could not move my finger (i.e. with little effort I could

stop the flow of fluid).

[Kevin Brinkerhoff]

I agree with Gene, if mc is good it will shoot fluid across room. Kevin

----- Original Message ----- From: "Gene Gillam" anngene@bellsouth.net> To: mg-tabc@yahoogroups.com> Sent: Friday, May 20, 2005 7:06 PM Subject: RE: [mg-tabc] Brake Fluid Pressure > Peter wrote: >>The pressure could not move my finger (i.e. with little effort I could > stop the flow of fluid). > Peter, > > I haven't seen that addressed by anyone yet - unless there's massive > amounts of air in the lines, when you press on the brake pedal you > should easily blow fluid past your fingertip - there's no way you could > hold it in with finger pressure. > > Have you tried removing the line from the back of the master cylinder > and then pressing on the pedal while trying to keep your finger on the > outlet? If you can't build up pressure here you've got a problem with > your master cylinder. If your finger can't hold the pressure then > you've got a problem else where. > > Gene Gillam > Saucier, MS > > > -- > No virus found in this outgoing message. > Checked by AVG Anti-Virus. > Version: 7.0.322 / Virus Database: 266.11.14 - Release Date: 5/20/2005 > > > > > > Yahoo! Groups Links > > > > > > >