Brake brain ache

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chips01
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Brake brain ache

Post by chips01 » Mon Mar 04, 2019 7:26 pm

Again I am visiting the fountain of knowledge and I cannot thank you all enough for the help you have given. This time my problems with brakes.

It is a 1977 SE6A. Have fitted new lockheed brake master cylinder. New dot 4 fluid. Front calipers have new brake pads, flexi pipes, discs skimmed, new seals and been stripped and polished. Rear drums have new shoes and cylinders been stripped and polished. Have tried two second hand brake balance valves and ensured air flows through all openings.

Front brakes have been bled. BUT no fluid is going to the rear brakes. Pedal travels to the floor. Have eezi bleed at 15 psi connected with both rear bleed nipples open but not even air being pushed out.

Is a fault with the brake balance the only thing left or is there something else ?

What the devil am I missing ?



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scimjim
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Brake brain ache

Post by scimjim » Mon Mar 04, 2019 8:18 pm

A crushed pipe halfway down the chassis? Did you try blowing them through with the bias valve removed?


Jim King

SECURE DRY STORAGE FOR YOUR SCIMITAR

Current: SE5 (8Ball), TI SS1 (snotty), 1600 SS1 (G97), 1600 SS1 (C686CCR), 2.5TD SE5a (diesel 5a), 6 x random other SS1s.
Previous: SE5, 3 x SE5a, 2 x SE6a, 3 x SE6b, GTC, 2.9i GTC, 3 x 1600 SS1, 1300 SS1, Mk1 Ti Sabre, Mk1.5 CVH Sabre
Chief mechanic for: 1400 K series SS1 (Megan3), 1400 CVH EFi SS1 (Grawpy), 1300 SS1 (Number One) & Sarah's coupe.
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Brake brain ache

Post by gtcse8 » Mon Mar 04, 2019 8:47 pm

Sounds like the Brake bias valve has worked, and is closed in the forward position.
Had it happen to me just the once when a rear pipe split.
It can be brought back into work by just swapping the two out pipes over and jumping on the pedal.
If its the valve at fault you should be able to bleed the rears.


Mark Wilson. See the Beast on youtube under" RELIANT SCIMITAR CONVERSION LOL.,Se5,Se5a, Se6a, Two Se6b`s,1 & 1/2 GTC`s, SST 1800Ti & not a lot of sense

chips01
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Brake brain ache

Post by chips01 » Mon Mar 04, 2019 8:55 pm

scimjim wrote:
Mon Mar 04, 2019 8:18 pm
A crushed pipe halfway down the chassis? Did you try blowing them through with the bias valve removed?
That was a thought I was having when typing this item. Unlikely but I shall have to look. Going to try blowing through with an airline as well.

The brakes were in a hell of a state but you cannot skimp on something like this.



chips01
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Brake brain ache

Post by chips01 » Mon Mar 04, 2019 9:03 pm

gtcse8 wrote:
Mon Mar 04, 2019 8:47 pm
Sounds like the Brake bias valve has worked, and is closed in the forward position.
Had it happen to me just the once when a rear pipe split.
It can be brought back into work by just swapping the two out pipes over and jumping on the pedal.
If its the valve at fault you should be able to bleed the rears.
Brake bias valve has been a struggle. I tested by blowing air through to two openings which are fed by master cylinder and air came out of the other holes so I assumed that all was clear. I will try the pipe swap and will also try forcing air down the rear pipe. Valve must be locked forward as no fluid going to the rear yet the pedal travels down to the floor.



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Roger Pennington
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Brake brain ache

Post by Roger Pennington » Mon Mar 04, 2019 9:16 pm

chips01 wrote:
Mon Mar 04, 2019 9:03 pm
Brake bias valve has been a struggle. I tested by blowing air through to two openings which are fed by master cylinder and air came out of the other holes so I assumed that all was clear.
Just a thought, but have you checked that the master is pumping fluid out of the ends of both the pipes leading into the bias valve?


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Brake brain ache

Post by scimjim » Mon Mar 04, 2019 9:32 pm

Yep, I think you need to crack each junction from master to slaves to see where the fluid actually stops - that’ll narrow down or even confirm where the fault lies.


Jim King

SECURE DRY STORAGE FOR YOUR SCIMITAR

Current: SE5 (8Ball), TI SS1 (snotty), 1600 SS1 (G97), 1600 SS1 (C686CCR), 2.5TD SE5a (diesel 5a), 6 x random other SS1s.
Previous: SE5, 3 x SE5a, 2 x SE6a, 3 x SE6b, GTC, 2.9i GTC, 3 x 1600 SS1, 1300 SS1, Mk1 Ti Sabre, Mk1.5 CVH Sabre
Chief mechanic for: 1400 K series SS1 (Megan3), 1400 CVH EFi SS1 (Grawpy), 1300 SS1 (Number One) & Sarah's coupe.
CURE THE FAULT - NOT THE SYMPTOMS

chips01
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Brake brain ache

Post by chips01 » Tue Mar 05, 2019 2:15 pm

Got it. Flexi from the copper brake line that goes down the chassis and along the rear axle then enters a 3 way junction is not letting brake fluid through. Will be replacing the rear flexi brake pipe and stripping and cleaning the rear junction. Let us hope and pray that will be the end of it.



chips01
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Brake brain ache

Post by chips01 » Tue Mar 05, 2019 3:10 pm

This is a photo of my rear brake flexi that has been left and not used for 18 years. Blocked solid. Think that may be why no brake fluid was going through
IMG_3447.JPG
IMG_3447.JPG (108.4 KiB) Viewed 1373 times
IMG_3445.JPG
IMG_3445.JPG (71.52 KiB) Viewed 1373 times



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Brake brain ache

Post by gtcse8 » Tue Mar 05, 2019 3:25 pm

Certainly wouldn`t help.
BUT, fluid should still be pushed along the lines out of the master.
Presuming the master rear seals are working.


Mark Wilson. See the Beast on youtube under" RELIANT SCIMITAR CONVERSION LOL.,Se5,Se5a, Se6a, Two Se6b`s,1 & 1/2 GTC`s, SST 1800Ti & not a lot of sense

chips01
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Brake brain ache

Post by chips01 » Tue Mar 05, 2019 4:03 pm

The master is new and all the front is new apart from hydraulic lines. Have fluid to rear axle now and the rear junction is now stripped and clean. Just waiting for Graham Walker to get back to me about the rear brake flexi. I am confident that once I get new fluid to the rears it should be fine. Famous last words.



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Brake brain ache

Post by scimjim » Tue Mar 05, 2019 4:35 pm

Excellent - I picked up a set of braided hoses for the SS1 last time I was at GWs - much cheaper than eBay and guaranteed to be the correct ones.


Jim King

SECURE DRY STORAGE FOR YOUR SCIMITAR

Current: SE5 (8Ball), TI SS1 (snotty), 1600 SS1 (G97), 1600 SS1 (C686CCR), 2.5TD SE5a (diesel 5a), 6 x random other SS1s.
Previous: SE5, 3 x SE5a, 2 x SE6a, 3 x SE6b, GTC, 2.9i GTC, 3 x 1600 SS1, 1300 SS1, Mk1 Ti Sabre, Mk1.5 CVH Sabre
Chief mechanic for: 1400 K series SS1 (Megan3), 1400 CVH EFi SS1 (Grawpy), 1300 SS1 (Number One) & Sarah's coupe.
CURE THE FAULT - NOT THE SYMPTOMS

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Brake brain ache

Post by Roger Pennington » Wed Mar 06, 2019 12:26 pm

That certainly looks like your problem! :shock: As per Jum's comment, I'd go for braided replacements, given a choice


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