Brake Fluid Weep, Uprated AP Brakes

[swsambler]

Sitting in my garage on this sunny day in Yorkshire wishing that I had my IVA appointment (still waiting), looking at my expectant vehicle, longing for a run up the Dales.

 

I have noticed a weep of brake fluid from the point of connection of the braided hose to the AP uprated fron disc caliper on my new build Roadsport 175.

 

I have tried tightening the connections, but to no avail over the last three days. The weep is less but still there.

 

Has anybody experienced this before or got any ideas how to cure it?

 

I have applied british standard nip to all connections, but realy do not want to tighten them anymore for fear of the inevitable shear.

 

I have searched the archives and note that some rear calipers had this issue and were faulty, but haven't seen any posts on the uprated AP front calipers.

 

 

 

Simon

 

Roadsport 175 SV

[jeffi]

Hi Simon - funny you mention that! I've got exactly the same issue - a very tiny weep from the AP caliper. I bled and finished them off last weekend and noticed this today when I was fitting the cycle wings. My leak is from around the copper washer where the union fits. The union was torqued to the correct setting, but I decided to tighten it a fraction today and see what happens. I've cleaned off all signs of fluid so if I get more, I'll drain down and fit an new washer, or may decide to leave it for CC to sort on the PBC as it could be a dodgy union or caliper body. I'm very reluctant to tighten further given my knack for stripping threads these days!

Jeff

[Pezky]

I think the copper washers Caterham supply are a bit too big and leak if not centered when fitting - at least this is what happened to mine when I fitted upgrated brake calipers.

 

I got some smaller washers from halfords - fixed.

 

 

 

penn7's pesky xflow

[swsambler]

Thanks for the advice and support. I will look into the smaller washers tomorrow.

 

Simon

 

Roadsport 175 SV

[myothercarsa2cv]

I've been told that blowtorching copper washers 'til they're cherry red then drowning them in cold water makes them extra crushable...

 

John

_________________________

 

myothercarsa2cv

Bugsy: '82 2cv6 😬

Talloulah '08 1.6K Classic

[swsambler]

Well, have stripped the brake lines to the caliper right back today. Inserted new copper washers and then cleaned and reassembled everything. Re bled the brakes and........ yes they still weep from the washer caliper connection.

 

Oh! well a call to Caterham tomorrow. 😔

 

Simon

 

Roadsport 175 SV

[swsambler]

Spoke to Caterham today and was advised that there have been some issues with this recently. Was advised to check flatness of the caliper face and the ingress of caliper black paint in the area where the washer should sit.

 

I checked the AP website and the torque figure for the male to male insert into the caliper is 25NM. (I think that is twice Caterham's figure). I have torqued them to this figure this evening, which was only a tweak from my BS Nip. They are still showing a slight weep.

 

I plan to strip the set up and then clean surface of caliper with some smooth wet and dry and try again.

 

Hope it works this time.

 

Simon

 

Roadsport 175 SV

[jeffi]

Hi Simon,

 

My union junction to caliper body is still weeping despite a tighening the other night - but less than before. I mentioned this to a mechanic and they said it's either the washer or the finish on the body or a combination of both - they think a bit of emery may help here. He also said they can be significantly tighter than you expect, so this probaly means 25Nm!

 

Jeff

 

 

[swsambler]

Success!!!

 

I have been searching for some decent copper washers, (The halfords assorted box washers are too thin and do not have enough surface area), after much searching I ended up at my friendly Quickfit, they gave me two washers for free. They are thicker than the the standard ones with more surface area. Dimensions are as follows:

 

ID 9mm, OD 15mm and Thickness just under 2mm.

 

I cleaned them up with fine wet and dry by rubbing on a flat surface. Interesting that they did not initially clean up evenly, i.e. not flat.

 

I then followed the heating plan. Cherry red in the blow lamp and then immediately quench in water. I then rubbed dry all over o clean up.

 

I inspected the AP caliper at the interface, but this surface was clean and flat with no paint overun.

 

Th ID clearance on the washer was very tight on the male to male adapter with the washer having to be threaded on at the start. Making sure that I had the male to male adapter the right way round. (More thread turns on the caliper side, the thread is a good fit, if you get it the wrong way round the adapter feels wobbly as you wind it in.

 

With reference to the AP web site I then torqued the adapter and washer up to 25 Nm.

 

Fitted the braided brake line and then bled the brakes on both innner and outer bleed screws, tapping the caliper as I progressed. The bleed screws were then torqued back down to 15Nm.

 

It is now 4 hours later and there is no sign of a weep.

 

The key appears to be a good flat tempered washer of the right dimensions torqued up to the right setting.

 

Fingers crossed and time for a GIn and Tonic, the sun must be over the yard arm somewhere. Thanks for all the helpful comments as usual.

 

Simon

 

Roadsport 175 SV