SPAQ inboard disc brake

[Storkfoot]

I have just picked up one of these Vietnamese made disc brakes for a very reasonable price. It is second hand. I am aware that they are not without their issues but thought it worth a punt.

From an initial strip down I suspect that this particular brake has not been working well and has not been apart since it left Vietnam.



There is neglible lubrication, the spring on the actuator is pretty weak and the pads were wedged in so hard that I had difficulty in getting them out.

I am rebuilding an original actuator. I shall obviously lubricate the three posts and I may well remove the circlip. I shall replace the pads with good ones which, if needed, will be dressed to make sure they are not both totally static.

Is there anything else I need to be mindful of?

[Fast n Furious]

Only the usual inherent design flaw with all these brakes.
All sorts of remedies have been tried to make these brakes work better but there becomes a point that you cant go beyond because the pressure applied to the brake pad equals the pressure applied in the opposite direction to the circlip. After a certain point, you can't apply any more braking force because the pressure begins to flex and distort the circlip trying to push it out of its groove. This is the spongy feel you get at the lever as well as cable stretch/contraction. If the circlip groove is worn or is not deep enough then this makes things worse.

[vegansydney]

A friend of mine had one of these several years ago and the only issue was the machining of the circlip groove that holds the actuator in place. I believe it needed to be cleaned up or shimmed slightly. I can't remember exactly, its been a while, but I'd highly recommend a dry build before painting / powdercoating.

[dickie]

I tried to make one of these work well a couple of years ago.

Problems I found were that the actuator was too tight in the grooves to return properly because the lugs on the actuator were larger than original. You could remedy this either by filing down the lugs or opening up the slots they ride in.

But the main issue was the shape of the detents in the actuator for the ball bearings. The original ones were conical, so you got uniform displacement for lever travel. On the remade ones, they were all concave, meaning that for the first part of lever travel, there was almost no movement, but by the time the balls had hit the steeper part of the detent, the lever was at, or close to the bar. This gave a spongey feel and very poor force on the pads. I bought several different actuators and tried a few springs and different diameter ball bearings, before i realised it was the shape of the detent and found an original actuator which sorted my woes.

[coaster]

I bought a used ScootRs version which had an issue with the circlip groove. I ended up buying a hydraulic converted actuator side and it has been a great brake, locked the wheel solid on the MOT rollers

[Storkfoot]

Thanks very much for those replies. I shall look into all those points throughly.

I didn’t pay attention to the circlip groove when I quickly took it apart this afternoon but I did notice that the actuator lugs were a tight fit, come to think of it. As I said, I am not going to use the SPAQ actuator. I’ll see what an original actuator fits like.

Any feedback on the disc itself? I had heard that they were tight on the pins but it seems okay to me.

[Warkton Tornado No.1]

With any inboard disc nowadays, through experience gained, I always just clean up the disc bore & pin holes, the hub's disc mounting surface & pins, the anti-rattle circlip & groove' then check that it all slides axially prior to applying Copaslip & reassembly. I also Copaslip the backs & sides of the pads. For hydraulic race inboard discs, I remove the static adjust screw & fit large shims/washers which tends to stop the static pad rotating. Or should that be ovulating?

There were methods adopted back in the '60's to overcome problems that no longer need be used because of advances in knowledge & consumables in the present day.

Regarding the actuator circlip, a good European manufactured replacement item will be extremely strong & flat. I don't have the shear strength to hand, but it would take more than the alloy backplate could handle to break one. If you can improve the seating face area & apply a small chamfer to the outside diameter edge of the circlip, any likelihood of lost motion will be virtually eliminated. IMO a greater gain would be had by an even stouter, pre-stretched stainless 'rope' type cable....

[dickie]

Yes, I forgot about the disc being tight. The groove for the anti-rattle clip is machined too deep, which allows the clip to apply more force on the pins.

When I was doing mine, I had a mate's original TV200 for rebuild, so I could easily compare the two. Shame I'm such a nice chap or he'd have inherited one or two parts

Obviously, you can leave it out or look for an original disc. But what I did was tighten the radius of the anti-rattle clip in a vice so that it was effectively "weaker". Was an easy job, but I remember having to be careful not to go so far that the clip was useless.

[hullygully]

Only the usual inherent design flaw with all these brakes.
All sorts of remedies have been tried to make these brakes work better but there becomes a point that you cant go beyond because the pressure applied to the brake pad equals the pressure applied in the opposite direction to the circlip. After a certain point, you can't apply any more braking force because the pressure begins to flex and distort the circlip trying to push it out of its groove. This is the spongy feel you get at the lever as well as cable stretch/contraction. If the circlip groove is worn or is not deep enough then this makes things worse.

I had this problem of the circlip flexing so I drilled & tapped 2 x holes above the circlip to retain it

[Fast n Furious]

Only the usual inherent design flaw with all these brakes.
All sorts of remedies have been tried to make these brakes work better but there becomes a point that you cant go beyond because the pressure applied to the brake pad equals the pressure applied in the opposite direction to the circlip. After a certain point, you can't apply any more braking force because the pressure begins to flex and distort the circlip trying to push it out of its groove. This is the spongy feel you get at the lever as well as cable stretch/contraction. If the circlip groove is worn or is not deep enough then this makes things worse.

I had this problem of the circlip flexing so I drilled & tapped 2 x holes above the circlip to retain it

I've thought about doing similar before but there's not a lot of ally here to bear the forces on 2 threaded pins but heyho if you've made it work then good for you. I may have to revisit this issue one day.

[Storkfoot]

I have just compared this SPAQ hub with an original.

As has been mentioned, the actuator lugs on the SPAQ one are a bit rough and ready and are about 1.0mm wider than an original actuator. The SPAQ one, consequently, catches on the hub slightly when you assemble it.

The circlip groove on both hubs is virtually identical at 2.06mm in width. This hub looks like it was initially supplied unpainted or powder coated so it is easy to see the definition of the groove. All appears good. The SPAQ supplied circlip is only 1.4mm as opposed to the one on the original hub (I very much doubt the circlip is original) which is 1.7mm.

Hopefully, simply replacing the circlip will assist the operation of the actuator which I shall be reverse pulling.