Over Tightened Brake Pipes?

[Rich_p 23]

Sometime ago we replaced all the brake lines on my 309. we added braided hoses to the calipers, a new master cylinder, solid lines through the car and an adjustable bias valve leading on to a t piece that then split to the rears.

 

All was well and the brakes were good with a hard peddle. The only issue was the joint from the bias valve towards the back of the car was weeping ever so slightly as I don't think there was enough of a flare on the pipe/it was an odd union as there only a few threads to do up.

 

I wanted to rectify this so I kept tightening it until it stopped weaping. Having got the car out of the garage months later the brakes feel fairly non existant when I run it to the end of the cul de sac and back but the pedal is still hard.

 

Is it possible I have overtightened and crushed the pipe? Or is it just where it's been sitting unused and just needs a proper drive and a few stamps on the pedal?

 

Just to add I believe it's a compbrake bias valve and I've ready they may be imperial rather than metric?

 

Someone on here kindly sent me an adaptor that he used when he had a compbrake valve but it wouldn't fit mine?

 

Idealli I'd like to re flare the pipe and add new unions but I'm really not sure what to buy!

Edited August 2, 2012 by Rich_p

[pug_ham 244 3 Cars]

If the flare was properly done then it should bottom out in the master cylinder / hose / bias valve etc.

 

Last time I had problems with a leaky pipe join was due to the M10 male / male union in a flexi hose end not seating fully home in the T piece on a 1.6 so it weaped.

 

The pipes should have a double flare which if done correctly would be very awkward to over tighten & close the central hole before stripping the bias valve body imo.

 

You need to know the make of the bias valve to be certain to get the correct thread union for the pipes into & out of the body, 3/8 unf is very similar to M10 x 1 but will strip in the body when tightened enough to seal.

 

g

[mikeyd 13]

had similar problem with a compbrake bias valve leaking -- [they are rubbish ! --got some bronze linkage bushes from them which had to be returned for re machining] --used a brake sealing compound to seal it but as mentioned they use a non metric thread

if you contact compbrake then be prepared for a £10 delivery charge !!

[Rich_p 23]

Found a photo before it was fitted. It appears the unions on mine differ to the ones in the 2nd photo. That appears to have a male threaded joint on the outside & mine had female. Could that make a difference?

 

The silver union on mine only went in by a few turns too.

 

Edited August 7, 2012 by Rich_p

[pug_ham 244 3 Cars]

Found a photo before it was fitted. It appears the unions on mine differ to the ones in the 2nd photo. That appears to have a male threaded joint on the outside & mine had female. Could that make a difference?

 

The silver union on mine only went in by a few turns too.

Yes, that could make all the difference & explain why you have a leak.

 

I had a similar issue with the n/s rear brake flexi around the beam on a 1.6 earlier this year & that was caused by the end of the union I'd used because I couldn't source the correct hose in the time period before I needed the car not sealing in the T piece correctly so fluid could still leak through the threads on the union.

 

The silver union only going in a few turns also hints at it being the wrong thread or they are damaged, the correct thread should run right in until it bottoms out.

 

The unions shown in the valve body in your second picture would also use a different single flare on the pipe end imo rather than the usual double flare of the 205 GTI brake lines.

 

g

[Anthony 1,002]

Are you absolutely sure that you've got the right unions?

 

M10x1 and 1/8" NPT for example are very similar and will screw into one another to a point, and the former is used on most Peugeot (and other European) fittings whereas the later is used on most American and aftermarket stuff. Only screwing in a few turns is usually what happens when you've got mis-matched fittings/threads, and will usually leak under pressure.

 

The poor brakes now are most likely from it sitting and chances are will sort themselves out after a few applications of the brakes. Most of the braking is done by the front anyway, although clearly the rears not working would have a very noticeable impact!

 

Easy way to prove is to attempt to bleed the rear brakes through - if the bias valve or line isn't allowing fluid through, then you'll find it very difficult to bleed with little more than a trickle/dribble coming out of the nipple.

[Rich_p 23]

Are you absolutely sure that you've got the right unions?

 

 

Sadly not, it was purchased as 2nd hand, fitted but unused and I just used the unions that were sent with it so chances are they are not correct.

 

Looking on the compbrake site I think these are probably what I need to order along with a pair of female m 10 x1 unions.

Does that sound about right?

 

http://www.compbrake.com/brake-kits/unions/1-8npt-to-m10-x-1-0-straight-caliper-union.html

[Rich_p 23]

Just had a thought, the adaptors I was sent may well actually fit. God knows where they are now!

[rikky 37]

you would get pre-threadlocked adapters with it when buying new obviously, i did with mine. i had this with a Wilwood one. also on the overtightening note, i had to tighten them practically in a vice as they went in so tight (to Wilwood's advice!)

Edited August 13, 2012 by rikky

[pug_ham 244 3 Cars]

I expect you'll find those adaptors cheaper on an auction site.

 

g

[Rich_p 23]

I expect you'll find those adaptors cheaper on an auction site.

 

g

 

Cheers Graham, I actually spotted them after writing my post.

 

I'm assuming those and standard M10 x1 female unions will work?

Edited August 14, 2012 by Rich_p

[pug_ham 244 3 Cars]

You did find the correct 1/8NPT to M10 x 1 adaptors & not straight M10?

I'm assuming those and standard M10 x1 female unions will work?

they should run straight on, the pipe flare will need re-doing to a single flare to seal correctly imo.

 

g

[Rich_p 23]

2 of these

 

http://www.ebay.co.uk/itm/120944365079?_trksid=p5197.c0.m619

 

and a pack of these

 

http://www.ebay.co.uk/itm/Brass-Female-Brake-Fitting-Union-M10-x-1mm-10PC-FL8-/110896765644?pt=UK_Cars_Parts_Vehicles_Other_Vehicle_Parts_Accessories_ET&hash=item19d1f65acc

 

Is that correct?

[pug_ham 244 3 Cars]

Should be.

 

g