Doug Foster Posted October 14, 2023 Report Share Posted October 14, 2023 I have a 1975 TR6 and have been having a problem with my front brakes seizing on me after a moderate drive (2 miles plus). I changed my one front caliper that was seized ( guess I should have done both) took for a short drive and immediately jacked up and both wheels very tough to rotate. So I asked around and ended up changing all brake lines. Reservoir I changed quite a short time ago. Took car for a test drive today, again a moderate drive. By the time I got home both fronts seized and Divers side smoking. The only things I haven't done is the other caliper and the brake booster. Thoughts ??? I'm stumped Quote Link to post Share on other sites
Mk2 Chopper Posted October 15, 2023 Report Share Posted October 15, 2023 Sounds like the master cylinder, I had this when I fitted a new one as it wasn't adjusted correctly to the servo pushrod. Gareth Quote Link to post Share on other sites
John Morrison Posted October 15, 2023 Report Share Posted October 15, 2023 Hi Doug, other TR6 owners will be along, Welcome to our forum by the way, but set up between M/c and Servo is the likely culprit. See this;- front wheels (brakes?) smoking By MC1234, June 18 in TR6 Forum. John. Quote Link to post Share on other sites
FatJon Posted October 15, 2023 Report Share Posted October 15, 2023 Servo pushrod incorrectly adjusted. After a few miles the brakes will be locked solid and the pedal rock hard. Quote Link to post Share on other sites
rcreweread Posted October 15, 2023 Report Share Posted October 15, 2023 I would also change your front brake hoses if you haven't done that recently but more than likely it will be the servo pushrod adjustment Cheers Rich Quote Link to post Share on other sites
Waldi Posted October 15, 2023 Report Share Posted October 15, 2023 Welcome to the forum Doug, as said by Gareth and John, this is likely an adjustment issue of the little pushrod in the servo that pushes the master cylinder “in”. During driving the brake oil get’s warm and expands a bit in volume. That’s normal. The extra volume flows back to the reservoir if all works well. If the MC is just a little bit activated (pushed in), the connection to the reservoir is separated from the system by the tipping valve. Fluid can no longer return and the pressure in the oil increases. This will activate the brakes. Waldi Quote Link to post Share on other sites
harrytr5 Posted October 15, 2023 Report Share Posted October 15, 2023 Best practice is to change both calipers At the same time. Regards Harry. Quote Link to post Share on other sites
jerrytr5 Posted October 15, 2023 Report Share Posted October 15, 2023 Have you recently changed to silicone fluid? Sometimes doing this can have a similar effect. Jerry Quote Link to post Share on other sites
roy53 Posted October 15, 2023 Report Share Posted October 15, 2023 The pressure is staying in your pipes. Adjustment is your easy option but there was a yew years back a batch of dodgy master cylinders about eg tipping valves. Roy Quote Link to post Share on other sites
Doug Foster Posted October 15, 2023 Author Report Share Posted October 15, 2023 Thanks to all of you, yes I will check servo rod adjustment. Ya I really should have changed both calipers and yes I have changed all brake line including the flex lines on all four corners. But like I say I will check servo push rod adjustment. Cheers Quote Link to post Share on other sites
FatJon Posted October 16, 2023 Report Share Posted October 16, 2023 A useful tip. When the brakes lock on, hop out, spanner in hand and loosen the two nuts that hold the master cylinder to the servo by a 1/16". If it instantly releases the brakes you have found the culprit. You can put two washers under them as a temporary bodge to get you home. Quote Link to post Share on other sites
FatJon Posted October 16, 2023 Report Share Posted October 16, 2023 Correction, when I say under them I mean between servo and master cylinder. Quote Link to post Share on other sites
Waldi Posted October 16, 2023 Report Share Posted October 16, 2023 (edited) Now Jon, that is a good “get you home” tip! And above all, it will tell you if insufficient servo rod-clearance is the issue. Waldi Edited October 16, 2023 by Waldi Quote Link to post Share on other sites
PodOne Posted October 16, 2023 Report Share Posted October 16, 2023 7 hours ago, FatJon said: A useful tip. When the brakes lock on, hop out, spanner in hand and loosen the two nuts that hold the master cylinder to the servo by a 1/16". If it instantly releases the brakes you have found the culprit. You can put two washers under them as a temporary bodge to get you home. Nice tip Jon. I'd just pre cut some slots in the washers so they can be slid in like shims. Quote Link to post Share on other sites
Doug Foster Posted October 21, 2023 Author Report Share Posted October 21, 2023 On 10/16/2023 at 5:19 AM, FatJon said: A useful tip. When the brakes lock on, hop out, spanner in hand and loosen the two nuts that hold the master cylinder to the servo by a 1/16". If it instantly releases the brakes you have found the culprit. You can put two washers under them as a temporary bodge to get you home. Quote Link to post Share on other sites
Doug Foster Posted October 21, 2023 Author Report Share Posted October 21, 2023 Sounds like an easy test, I will give that a whirl once the weather improves. Cheers Quote Link to post Share on other sites
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