Brake Master cylinder

[Reckless Rat]

Hi everyone.
My MGF is currently at the local garage having the brake master cylinder replaced (I'm getting lazy). I bought the part through a national French parts supplier called oscaro.com, which is usually reliable. According to Oscaro the MG/Rover OEM part number is GMC90360.

The part they sent me is made by TRW and carries their part number PMK315 and is marked as suitable for the MGF and the TF. The "garagiste" called me this morning to say that it won't fit. Apparently everything is correct apart from the hydraulic connections to the master cylinder which on the car are of a larger diameter than the threads on the master cylinder and therefore they can't be connected.

The car is original. It's a RHD 1997 MGF with PAS & ABS, originally registered in the UK and then exported to France. The VIN n° is SARRDWBGAD0186**, 1st registered 22/3/1997. I can see that the original master cylinder hydraulic connections are of a much larger diameter than the replacement cylinder. Question I ask is how to sort it. Have I somehow got the wrong part or do I need to buy a couple of step-down adaptors?

I have sent an E-Mail to TRW asking them for their comments/help but as yet I've had no reply. Brown & Gammons also list only one master cylinder.

Any ideas or suggestions will be much appreciated as the car is currently languishing at the workshop and it's out in the open, something I'm not too happy about as it normally never gets wet...

Cheers
Bruce

[Helsbyman]

R R wrote it normally does not get wet [ another sissy car ha ha ]

[speakmanrp]

Some MG parts supplier have two options for the Brake Master Cylinder, with or without ABS.

Part number without ABS is SJC10005
Part Number with ABS is SJC10007

Brown and Gammons page for SJC10007 is http://www.ukmgparts.com/product.aspx?C ... 79c536517b

Hope this helps

[Reckless Rat]

Well it tells me that there are two different master cylinders and it looks like I've got the wrong one! Is there any way of obtaining the MG/Rover part numbers?

[Rob Bell]

Bruce, Speakmanrp has used the MG Rover part numbers above (SJC10005 and SJC10007) - more here on the Rimmers site: http://www.rimmerbros.co.uk/Item--i-GRID000300

Can you take a comparative picture of both master cylinders for the record? Thanks

[Reckless Rat]

Thanks for the update. I will post photos as & when. I'm still trying to locate the right part (apologies to Rimmer Bros but the SJC10007 is exorbitantly expensive compared to the other one.) This will get solved one of three ways:

1. I can locate the right master cylinder at a sensible price
2. I give up, send the master cylinder back for a refund and try a seal replacement kit
3. I fit the non-ABS cylinder which I have bought and modify the pipework to suit. The joints can be hidden behind the black plastic shield.

[Rob Bell]

Option 3 could be a good solution - you'd just need a couple of suitable unions and a short length of pipe to interface the existing pipework with the master cylinder you have.

Of course, another plan may be to obtain a good second hand replacement?

[Reckless Rat]

I'm certainly seriously considering the third option. There's absolutely no difference in the two master cylinders apart from the threaded diameter of the two outlets, and a quick pipe replacement jobby seems a sensible way round the problem. Where I live in this part of France an MGF or TF in itself is a rare object, and I would reckon that sourcing a second hand ABS version master cylinder round here is even less likely than François Hollande getting re-elected.

I'll let you know how it turns out.

[Geoff.F]

The important requirement is not the connection sizes but the piston bore size. Ensure that the replacement is the same.
Geoff.F

[Reckless Rat]

Point taken, Geoff. Both me and the "Garagiste" have looked at the two master cylinders and the only apparent difference is the threaded portion of the fluid outlets. We're going to go for option 3 and see how it goes.

I did check that the replacement MS is threaded metric too, because it would have been a bugger if we'd cut and chopped the hydraulic lines only to discover that the new MS was threaded imperial/UNF...

Car will be ready Monday. Mind you this is the south of France - he didn't say which Monday.

[Rob Bell]

Car will be ready Monday. Mind you this is the south of France - he didn't say which Monday.

That applies to many parts of the UK too!

[Reckless Rat]

R R wrote it normally does not get wet [ another sissy car ha ha ]

One (or several) of the reasons why I'm not happy about my little car being left out in the open....

http://www.midilibre.fr/2014/10/10/inte ... 063798.php

and it's still raining.

[Reckless Rat]

A quick update on the master cylinder replacement.

The job was completed several weeks ago, with new olives formed on the existing lines to the m/c, with 10mm nuts to suit the threads. Since then the system has been bled until I'm blue in the face but I'm convinced there's still an air lock somewhere. First application of the brake the pedal is not hard and slowly goes towards the floor. Second and subsequent application the pedal is hard and at the top of its travel, which suggests to me that the problem is air in the system and not pressure bleeding past the m/c seals.

There are no leaks nor loss of fluid.

The only suggestion I can come up with is that there is air trapped in the ABS motor somewhere.

Has anyone had similar problems with an ABS equipped MGF?

[talkingcars]

Did they bleed it by drawing fluid at each corner or vacuum bleeding?

[Reckless Rat]

We did it by drawing fluid at each corner, as per the w/manual but I think I'm going to have to try a vacuum bleed. The design of the master cylinder top precludes a pressure bleed because you can't screw the adaptor on to the reservoir.

[talkingcars]

I started to adapt a normal reservoir cap to take the pressure bleed kit until I found out how cheap a vacuum bleed was at the local garage.

[Rob Bell]

I vacuum bled Project Shed (ABS) - using an air-powered Sealey bleed gun. It seemed to do a good job

[Reckless Rat]

I think I'm going to go that route, Rob. Will spend some beer tokens after the Christmas binge-fest.

[cbjroms]

I have been advised, on another forum, that TRW's part number PMK315 might be an alternative to the SJC10007 which, I have been told by Xpart, is no longer available.

A Google search brought me to this thread and I am wondering whether OP (Reckless Rat) found that, having modified the brake line fittings, the PMK315 is suitable for an MGF with ABS.

[Reckless Rat]

I went for option 3 and the braking system (as well as the ABS) has been working fine ever since.