Blocked brake pipe

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Bikergonebald
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Blocked brake pipe

Post by Bikergonebald » Sun Apr 19, 2020 9:08 pm

Hi,
I've been servicing my brakes and got to flushing through the brake fluid. I started at the rear right with a vacuum bleeder but it hardly pulled out any fluid so I did it the old fashioned way but the fluid was flowing real slow and there was resistance on the pedal.
I moved to the other side and the vacuum pulled it through OK but then I let the level in the master cylinder get too low and air went in. Now I can't get anything through on the right because I can't build up any pressure.

I disconnected the union where the flex joins the steel pipe under the wheel arch and the pedal couldn't push any fluid out of there. So it seems I have blockage.

Any suggestions where to start looking? I'm hoping there''s a known block point so that I don't have to strip everything.

It passed it''s MOT 4 weeks ago.

Thanks for any help you can offer.

Kevin
Owner of a 1992 Mazda MX-6 Auto, 2001 Jaguar XK8 and 1982 Honda CB900c.
Sorry guys I don’t have a probe (yet ;) ) I’m asking questions here because I get better responses than on the US Mazda forum.

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Re: Blocked brake pipe

Post by Micron » Sun Apr 19, 2020 9:32 pm

Try disconnecting the pipe at the inlet side of the abs pump and see if anything comes through and then again the out let side.
At least you will then know if it's the pump?
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Re: Blocked brake pipe

Post by jrh » Mon Apr 20, 2020 8:43 am

I think ,perhaps, the ABS unit stops the system from being sucked dry.
You have no choice now but to flush the whole system from 'the top' , one wheel at a time.

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Bikergonebald
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Re: Blocked brake pipe

Post by Bikergonebald » Mon Apr 20, 2020 11:49 am

Hi micron,

If it's a problem with the ABS pump can they be reconditioned? A had a quick look on the internet and can't see any new.

I had suspected some problem with the ABS because once when i did have to brake hard the front left wheel locked, this is part of the reason why i'm giving the brakes a thorough service.

Thanks
Kevin.
Owner of a 1992 Mazda MX-6 Auto, 2001 Jaguar XK8 and 1982 Honda CB900c.
Sorry guys I don’t have a probe (yet ;) ) I’m asking questions here because I get better responses than on the US Mazda forum.

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Re: Blocked brake pipe

Post by Micron » Mon Apr 20, 2020 4:49 pm

Bikergonebald wrote:
Mon Apr 20, 2020 11:49 am
Hi micron,

If it's a problem with the ABS pump can they be reconditioned? A had a quick look on the internet and can't see any new.

I had suspected some problem with the ABS because once when i did have to brake hard the front left wheel locked, this is part of the reason why i'm giving the brakes a thorough service.

Thanks
Kevin.
It's very likely that the pump on a Ford Probe will be the same for a MX-6, so ask on here to see if someone has one.

Not sure if you can buy them new, the other option might be to have it reconditioned?
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Bikergonebald
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Re: Blocked brake pipe

Post by Bikergonebald » Mon Apr 20, 2020 8:27 pm

I just tested it and I get fluid from both of the inputs and the outputs. I also tried at the unions on the bulkhead for the rear brakes, is it a balance valve?

So the next job will have to be trying to blow through the blocked line.
Owner of a 1992 Mazda MX-6 Auto, 2001 Jaguar XK8 and 1982 Honda CB900c.
Sorry guys I don’t have a probe (yet ;) ) I’m asking questions here because I get better responses than on the US Mazda forum.

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Re: Blocked brake pipe

Post by Kit » Mon Apr 20, 2020 9:56 pm

iirc, there are two types of ABS pumps used on these cars & the brackets are not interchangeable :roll:

Kit

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Bikergonebald
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Re: Blocked brake pipe

Post by Bikergonebald » Fri Apr 24, 2020 8:54 pm

I disconnected what I thought was the blocked pipe and I blew it through with compressed air. I connected it again at the front but still couldn't get any fluid through it. What I did notice was that I have a firm pedal even though that pipe isn't connected to the caliper.

So it looks like I will need to get the ABS pump checked but first does anyone know what the union block is on the front bulkhead that the back pipes go through. Is it just a connector block or does it have some sort of valve in it?

Thanks guys.

Kevin.
Owner of a 1992 Mazda MX-6 Auto, 2001 Jaguar XK8 and 1982 Honda CB900c.
Sorry guys I don’t have a probe (yet ;) ) I’m asking questions here because I get better responses than on the US Mazda forum.

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Bikergonebald
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Re: Blocked brake pipe

Post by Bikergonebald » Sat Apr 25, 2020 2:36 pm

I think you guys might have been right about the ABS pump. I took both rear pipes completely out of the pump body. Fluid flows freely under gravity from one port, the other I get nothing even when pushing the pedal although the pedal is firm.
Owner of a 1992 Mazda MX-6 Auto, 2001 Jaguar XK8 and 1982 Honda CB900c.
Sorry guys I don’t have a probe (yet ;) ) I’m asking questions here because I get better responses than on the US Mazda forum.

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Re: Blocked brake pipe

Post by Jon G 24V » Sat Apr 25, 2020 7:38 pm

Bikergonebald wrote:
Fri Apr 24, 2020 8:54 pm
I disconnected what I thought was the blocked pipe and I blew it through with compressed air. I connected it again at the front but still couldn't get any fluid through it. What I did notice was that I have a firm pedal even though that pipe isn't connected to the caliper.

So it looks like I will need to get the ABS pump checked but first does anyone know what the union block is on the front bulkhead that the back pipes go through. Is it just a connector block or does it have some sort of valve in it?

Thanks guys.

Kevin.
Think this Valve is the Front to Rear bias Valve.

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