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1980 TR7 Brake Problem.

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1980 TR7 Brake Problem.
#1
  This topic is about my 1980 Triumph TR7
Lagodude Avatar
Lagodude Garry Bayer
Lago Vista, Texas, USA   USA
I have replaced all brake components.

Shoes, Pads, cylinders, drums, calipers, rotors, hoses, Brake Balance Pressure Reducing Valve and Uprated Brake Master Cylinder and Servo Assembly.

I have bench bled the master and have bled and bled the system (tried gravity, speedy bleeders and conventional bleeding).

Still very little brakes in rear. No front brakes.

Anybody have any idea what i am doing wrong or suggestion of what I might try?

Appreciate any and all help,

Thanks,

GarryB

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darrellwalker Darrell Walker
Vancouver, Washington, USA   USA
1966 Triumph TR4A "Christy"
1981 Triumph TR8 "Kate"
When you bleed, do you get fluid flowing out?



Darrell Walker
66 TR4A IRS-SC CTC67956L
81 TR8 SATPZ458XBA406206
Vancouver, WA, USA

Lagodude Avatar
Lagodude Garry Bayer
Lago Vista, Texas, USA   USA
Hi Darrell,

Yes. I bleed completely and got clear, new fluid with no bubbles.

Went through a complete 32oz bottle of DOT4 fluid.

Thanks,

GarryB

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nick Avatar
nick nick m
Bend, OR, USA   USA
Be sure you have no leaks at any of the couplings under the car.



nick

TR8todd Avatar
TR8todd Todd Kishbach
Mass, USA   USA
1977 Triumph TR7 "Rally Fraud"
1978 Triumph TR8
1979 Triumph TR7
1980 Triumph TR8    & more
Can you be a little more specific about "very little rear and no front brakes"? Did you get fluid at the rear and both fronts? When you close the system, does the pedal go to the floor or is it firm? Do the front brake pistons move? Did you adjust the rear adjusters to take up all the slack? Did you clean the rotors with brake cleaner and lightly scuff the pads before you took the initial road trip? Give us some details as to whats happening.

FrankieD Frank D'Angelo
King George, Virginia, USA   USA
If you have any rubber "pipes" or lines, they may be expanding like a balloon) as you apply brake pressure; removing most of the pressure applied to the brake calipers/pistons. . If they are old, replace them.

Lagodude Avatar
Lagodude Garry Bayer
Lago Vista, Texas, USA   USA
Hey Guys,

Appreciate all your help and suggestions.

Here is were I am at:

All parts are new.

No leaks under the car, on the floor or on the chassis.

The rubber lines are new Stainless Steel Braided. Shouldn't be an issue.

I have bled many times, all the different ways. No bubbles.

I a test drive in my driveway, I seem to have some rear brakes (no front). Enough to slow the car but not enough to hold on any hill.

When I isolate the rear brake by capping off the front brakes at the master. I do have a solid peddle and rear brakes, again not great.

I have removed the calipers from the rotor and after pumping the pedal several time the pistons fully open to the point the pads touch one another. Used channels to close them using the tab and then reinstall.

The interesting thing is that when I remove the vacuum line at the servo I have better peddle and seemingly better brakes. Runs too rough the drive but they seem to work. I have removed the check valve at the fuel mixture chamber and cleans. It seems to be working correctly.

Any ideas?

I am totally stumped at this point.

Any help or suggestions are greatly appreciated.

Thank you all,

GarryB

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allzway Avatar
allzway James P
Paris, Texas, USA   USA
I had a similar issue with my car. Bleeding was great, pedal felt fine, but not real brakes with the car moving.

My car has a buick engine, but it turned out to be that I was not getting enough vacuum to the booster. Once I change the location vacuum was being pulled from they started working great.

So if you are running stock everything, could your booster be bad or no vacuum?

nick Avatar
nick nick m
Bend, OR, USA   USA
Could the master be bad? I have had a situation on an airplane recently (not exactly a TR7 of course) where no amount a bleeding would give me pedal pressure. I replaced both masters (one on each wheel) and now they work great. I know you said it is new but there really isn't anything left.



nick



Edited 1 time(s). Last edit at 2017-10-20 05:16 PM by nick.

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darrellwalker Darrell Walker
Vancouver, Washington, USA   USA
1966 Triumph TR4A "Christy"
1981 Triumph TR8 "Kate"
In reply to # 1492573 by Lagodude Uprated Brake Master Cylinder and Servo Assembly.

Tell us more about this part. Is it just that it takes a lot of pressure on the pedal to stop?

Maybe not your problem, but when I replaced my brake master (with a new stock unit), I forgot the rubber boot that seals the master to the booster (you don't get a new one with the master, you are supposed to reuse the old one, I guess). I had brakes, but it took a lot to stop. It also causes a vacuum leak, so the idle was high.



Darrell Walker
66 TR4A IRS-SC CTC67956L
81 TR8 SATPZ458XBA406206
Vancouver, WA, USA

Lagodude Avatar
Lagodude Garry Bayer
Lago Vista, Texas, USA   USA
Hi Darrell,

I purchased the "Uprated Brake Master Cylinder and Servo Assembly" from RimmerBros.

Part #RB7656

Came assembled.

The listing said "WILL MAKE THE BRAKE PEDAL SIT HIGHER ALSO." Sounded a little strange, their customer service said it will make a better system.

Have not removed master to see about rubber boot. Assume it's there but guess I should check.

I'll check tomorrow.

Thank you,

GarryB

POW Peter Wirth
HEBRON, NH - New Hampshire, USA   USA
I'm guessing all the new brake parts came from Rimmer Bros. I've ordered from them too with only one hitch over a V8 intake gasket. There own soft top and their own vinyl seat covers fit superb and the very reasonably priced driveshaft got rid of my vibration. Point is they are reliable and easy to talk to. I'd give them a call, explain what's up and go from there. I noticed the MC/servo is modified in some way. It's possible an inner seal got damaged or installed wrong. Only prob with Rimmers is the cost of getting things back to them. They'd more than likely make good on the back shipping if the part proved defective but how to prove that?

Lagodude Avatar
Lagodude Garry Bayer
Lago Vista, Texas, USA   USA
Hi Peter,

Thanks for the reply.

In my previous post I did not go back all the way to the start of this issue:

I purchased the car "As Is". Not running and had not been driven in many years.

Tackled the running issue first. Got running, not great but running.

Replaced shocks, struts and springs. Also replaced most rubber grommets on undercarriage.

Then went on to the brakes (not even sure if the were functioning before I ripped into them removing everything and starting new.

In my first Brake Parts order to Rimmer I did order a new master. I installed it on the original servo. I when on from there and rebuilt the brake system with all new parts (listed above). That's when this whole issue started. After experiencing problems, I replaced the servo with an aftermarket rebuilt one from another supplier. Continuing to experience the same problem I called Rimmer CS and they said it could be the servo and master not matched will (the push rod in the servo not pushing the master plunger correctly. So I ordered the present "Uprated Servo/Master".

Seems like the issue has improved but nowhere near the brakes necessary to have a road worthy car.

I guess it could be a bad new part from the manufacturer.

Baffling.

I think I am going to try to isolate the front calipers from the back brakes and bypass the pressure reducing valve. Bleed the system and see if that does not give me brakes in the front and the rear.

I'm sure that is not the complete answer but then I should know that the system is working.

Does that sound logical?

Appreciate the input.

GarryB

Darth V8R Avatar
Darth V8R Vance Navarrette
Beaverton, Oregon, USA   USA
1980 Triumph TR8 "Wedgie"
In reply to # 1492991 by Lagodude Hi Peter,

In my first Brake Parts order to Rimmer I did order a new master. I installed it on the original servo. I when on from there and rebuilt the brake system with all new parts (listed above). That's when this whole issue started. After experiencing problems, I replaced the servo with an aftermarket rebuilt one from another supplier. Continuing to experience the same problem I called Rimmer CS and they said it could be the servo and master not matched will (the push rod in the servo not pushing the master plunger correctly. So I ordered the present "Uprated Servo/Master".

Seems like the issue has improved but nowhere near the brakes necessary to have a road worthy car.

GarryB

Garry:

You certainly have thrown a lot of money at the problem. Yeowzah!

Have you tested the Servo to make sure it is doing its job? Start by pumping the brakes a few times, then depress and hold the pedal. Start the car. You should feel the pedal drop as the vacuum assist engages. Shut off the engine. Pump the brakes 3 or 4 times. You should feel the pedal suddenly firm up as the vacuum reserve in the servo is depleted and you lose the power assist. It should take at least 2 pumps before the brakes firm if everything is up to snuff.

You didn't say which hoses you replaced. I assume you replaced the front ones, what about the rear hose? Did that get replaced as well? What about the vacuum line to the servo - have you checked and or replaced it? Make sure it is not collapsing under vacuum, or is otherwise restricted. Is it connected directly to the intake manifold? is the fitting on the manifold free from obstructions?

You say the car is not running well. Any chance it has a vacuum leak or some other problem that prevents the servo from getting the vacuum it needs? A rough running engine will not generate much vacuum - especially if it has been cammed. Has the engine been cammed or otherwise modified? You will need at least 12 inches of vacuum, and better if you have 16 inches. You can search for vacuum leaks using an unlit propane torch, and spraying propane gas around the manifold and carbs. A sudden increase in RPM indicates a leak. Check your manifold vacuum with a vacuum gauge.

What kind of brake fluid are you using? It is from a tightly sealed container? If you are using DOT4 fluid, it should be clear. If it is brown it is contaminated with moisture - this would not keep you from getting a firm pedal however. Just trying to cover all the bases.

Make sure that there is nothing restricting the travel of the brake pedal itself. Carpeting, wiring, dead squirrels. Anything that prevents you from getting a full stroke of the pedal. Also check to make sure your right leg is as long as the left one (just kidding).

OK, that's my list.

Vance



1980 Platinum Metallic TR8, navy blue interior
Bare metal respray, Crower cam, raised compression
ported heads, modified Zenith carbs, 0.060" overbore

POW Peter Wirth
HEBRON, NH - New Hampshire, USA   USA
Garry, do you have a firm pedal but just no stopping power, or are you not able to get a firm pedal at all?

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