[TR] I story...

[DAVID MASSEY]

 A swollen hose is definitely a possibility and the most likely explanation for a single brake hang-up.  Another possibility for the front brakes staying engaged is that the tipping valve in the master cylinder is not getting actuated to relieve residual pressure when the brakes are released.  Your comment " she noticed the brake pedal just needed to be touched and she would be able to stop" suggests that either the pedal is not returning fully or the piston in the master cylinder is not returning sufficiently to engage the tipping valve.  

The tipping valve opens the passage between the front brake circuit and the reservoir.  As the fluid in the calipers warms up and expands the excess volume must vent to the reservoir to prevent the build-up of pressure and the resulting engagement of the pads. This failure will effect both front brakes equally.

The rear circuit has a similar device at the very end of the piston.  It is the little cup that blocks off the port to the rear reservoir.  I've seen one of those become disengaged causing the brakes to self-actuate.  This was on a Hearld (single circuit brakes) and cracking a bleeder resolved the problem in the short term.
 
Dave 

 
 
-----Original Message-----
From: Jeff Scarbrough <fishplate at gmail.com>
To: William Pugh <anabil007 at comcast.net>
Cc: TR3/6 <triumphs at autox.team.net>
Sent: Fri, May 21, 2021 5:11 am
Subject: Re: [TR] I story...

I didn't see any responses...so here's my thoughts.

1.  This is a typical symptom of swollen brake hoses.  Easy to check:
Jack up the car, and see if the wheel spins.  If so, apply the brakes
firmly and check to see if it's tight.  If so, open the bleed screw
and see if it now spins easier.  If so, probably need to investigate
new hoses.

2.  If you didn't have trouble getting the new pads in the calipers,
then the shim probably isn't the problem.

3.  Calipers can also fail.

4.  Is the problem on more than one wheel?  (This should have actually
been first - if it shows up on wheels that don't share a hose, look to
the master cylinder - or a problem with the new parts.)

On Tue, May 18, 2021 at 1:48 PM William Pugh <anabil007 at comcast.net> wrote:
>
> This winter we worked on getting the TR3 & TR6 in as good shape as possible
>
> Front and rear pads and liners were installed (new)
> TR6 enjoyed having all the old Hydralic fluid removed and replaced several other enhancements but I want to stick with the Front Brakes on TR6.
>        After the work was done we followed the Moss instructions “drive slowly up and down for a while, do not use brakes”  We did that, all seemed well, we slowly began using the brakes and all was well.
>        Then we took several short drives “avoiding hard braking”  10 miles, 20 miles, 50 miles we are being “good”.
>
> But … you knew this was coming … Yesterday AB drove to Lodi for a meeting with her PEO ladies, first time this year. No problem … coming through Lockford, CA a Fire Truck came out suddenly and she needed to get out of the way, pulled to curb, heavy braking. When all clear she started returning home 10 miles, no need for brakes, she the caught a Stoplight for several minutes and she noticed the brake pedal just needed to be touched and she would be able to stop…very worry because before the pedal had normal movement.
>
> She drove on home 5 miles and when she entered the garage the front disks were SMOKING!
>
> Nothing to do but wait for all to cool down.
>
> I have several pictures Rotor has sand melted on rim, some streaks on flat side. Why???
>
> Well they got to hot … yep … but why? When we removed the new disks, they were backed by a thin shim.  That was on the original pads as they grew smaller.  Is it possible that those shims put too much pressure and caused the serious overheating?  A small mind would like to know.
>
> I have photos if anyone is interested , all kind looks OK ,,,
>
>
> Thanks
> Bill & AnnaBelle
> Rosey TR6  1970
> Casper TR3  1957 (he is just fine)
>
>
> ** triumphs at autox.team.net **
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