Brake master Cyl seal kit- help

[ChrisR-4A]

Hi all, at the International I purchased from one of our reputable suppliers a seal kit for a Tr4A brake master cyl 0.7 ins bore.

I fitted the kit and could not get the brakes to bleed, I rechecked the assembly as per the Moss illustration and all was fine so I then measured the size of the seal at its widest dia. It was approx 0.765 ins, unfortunatly by this time the bin men had been and removed the old seal so I had a look in my spares box and found a seal kit for 0.700 ins rear wheel cyls, these seals are only 0.735 dia, and also I found a seal kit for a 0.750 clutch master cyl which was the same size as my susposedly 0.700 seal; so I think I may have been sold a kit for a 0.75 cyl and the seal may be folding on the lip and not making a good seal. In the meantime I have ordered a seal kit from my usual trusted supplier somewhere in Somerset and will try that in the next couple of days. Meanwhile can anyone confirm the wides dia of a 0.7 ins seal and of more concern has anyone else had this problem, I am concerned there may be seal kits out there with the wrong identification on them.

 

Chris

[ChrisR-4A]

Well the second seal kit arrived thismorning and there was a difference in the seal dia, (I was sold the wrong kit) it was smaller by about 20thous and when fitted the brakes bled first time.

I am fairly sure there is no air in the system, However I still have about 1.5 ins pedal movement before anything happens, if I pump the pedal a couple of times the play is taken up and then if I just slightly ease my pressure on the pedal and push again then there is still no play, But if I remove my foot completely an wait a couple of seconds the re apply the 1.5 ins play is back. The question is will a new mastercyl fix this, what are other owners brakes like?

The car is fitted with a remote servo which is about 7 years old, I have adjusted the rear brakes and the discs and pads are new this year.

 

Any suggestions much appreciated.

Regards Chris

[stuart]

Pump the pedal up to its highest and then jam it down with a bit of wood between the pedal and the seat and leave it overnight.

Stuart.

[Mark1965TR4aBRG]

I use a Draper Brake Bleeding kit that works on my compressor. This draws fluid from the bleed nipple under vacuum and in my experience works perfectly.

 

The original pump and push method for me has not been quite so reliable..

[ChrisR-4A]

Problem is resolved, set things up for a long bleeding session with a glass jar with steel weight taped to it so it would

not fall over when only 1/4 full and a new 1 litre bottle of brake fluid.

Got assistant to do 2 quick pumps and one slow and got loads more air out. 3/4 litre bottle of fluid later and pipe appeared

air free and pedal has about 1 inch movement before servo starts to slow you down. Can still reduce play a little with a couple

of pumps but it now compares well with other cars. Have held off buying a new master cyl for now as at over £100 I need to know if it will make any difference before I buy.

 

While in the mood I then fitted a new clutch slave cyl and had no problems at all. Although I checked before I started that

I had the correct parts, it does help. I may never buy any parts at the International again.

Previous suspect parts bought at Internationals include,

Master Cyl seal kit - subject of this post

Speedo cable - lasted less than one year

Clutch slave cyl- incorrect size supplied 7/8 instead of 1 inch ( took ages to realise why clutch was heavier than some other 4As.

 

The first item was from a supplier who supply lots of Tr Bitz

and the second two from a well known west london Shop.

 

Having said that I have bought many other parts from both the above suppliers by mail order and had no problems.

 

Chris